/*-------------------------------------------------------------------------
 *
 * ruleutils_15.c
 *	  Functions to convert stored expressions/querytrees back to
 *	  source text
 *
 * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  src/backend/distributed/deparser/ruleutils_15.c
 *
 * This needs to be closely in sync with the core code.
 *-------------------------------------------------------------------------
 */
#include "pg_version_constants.h"

#include "pg_config.h"

#if (PG_VERSION_NUM >= PG_VERSION_15) && (PG_VERSION_NUM < PG_VERSION_16)

#include "postgres.h"

#include <ctype.h>
#include <unistd.h>
#include <fcntl.h>

#include "access/amapi.h"
#include "access/htup_details.h"
#include "access/relation.h"
#include "access/sysattr.h"
#include "access/table.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_am.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_extension.h"
#include "catalog/pg_foreign_data_wrapper.h"
#include "catalog/pg_language.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_partitioned_table.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "commands/extension.h"
#include "commands/tablespace.h"
#include "common/keywords.h"
#include "distributed/citus_nodefuncs.h"
#include "distributed/citus_ruleutils.h"
#include "distributed/multi_router_planner.h"
#include "distributed/namespace_utils.h"
#include "executor/spi.h"
#include "foreign/foreign.h"
#include "funcapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "nodes/pathnodes.h"
#include "optimizer/optimizer.h"
#include "parser/parse_node.h"
#include "parser/parse_agg.h"
#include "parser/parse_func.h"
#include "parser/parse_node.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parser.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "rewrite/rewriteSupport.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/hsearch.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/ruleutils.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/typcache.h"
#include "utils/varlena.h"
#include "utils/xml.h"


/* ----------
 * Pretty formatting constants
 * ----------
 */

/* Indent counts */
#define PRETTYINDENT_STD		8
#define PRETTYINDENT_JOIN		4
#define PRETTYINDENT_VAR		4

#define PRETTYINDENT_LIMIT		40	/* wrap limit */

/* Pretty flags */
#define PRETTYFLAG_PAREN		0x0001
#define PRETTYFLAG_INDENT		0x0002

/* Default line length for pretty-print wrapping: 0 means wrap always */
#define WRAP_COLUMN_DEFAULT		0

/* macros to test if pretty action needed */
#define PRETTY_PAREN(context)	((context)->prettyFlags & PRETTYFLAG_PAREN)
#define PRETTY_INDENT(context)	((context)->prettyFlags & PRETTYFLAG_INDENT)


/* ----------
 * Local data types
 * ----------
 */

/* Context info needed for invoking a recursive querytree display routine */
typedef struct
{
	StringInfo	buf;			/* output buffer to append to */
	List	   *namespaces;		/* List of deparse_namespace nodes */
	List	   *windowClause;	/* Current query level's WINDOW clause */
	List	   *windowTList;	/* targetlist for resolving WINDOW clause */
	int			prettyFlags;	/* enabling of pretty-print functions */
	int			wrapColumn;		/* max line length, or -1 for no limit */
	int			indentLevel;	/* current indent level for prettyprint */
	bool		varprefix;		/* true to print prefixes on Vars */
	Oid			distrelid;		/* the distributed table being modified, if valid */
	int64		shardid;		/* a distributed table's shardid, if positive */
	ParseExprKind special_exprkind; /* set only for exprkinds needing special
									 * handling */
	Bitmapset  *appendparents;	/* if not null, map child Vars of these relids
								 * back to the parent rel */
} deparse_context;

/*
 * Each level of query context around a subtree needs a level of Var namespace.
 * A Var having varlevelsup=N refers to the N'th item (counting from 0) in
 * the current context's namespaces list.
 *
 * The rangetable is the list of actual RTEs from the query tree, and the
 * cte list is the list of actual CTEs.
 *
 * rtable_names holds the alias name to be used for each RTE (either a C
 * string, or NULL for nameless RTEs such as unnamed joins).
 * rtable_columns holds the column alias names to be used for each RTE.
 *
 * In some cases we need to make names of merged JOIN USING columns unique
 * across the whole query, not only per-RTE.  If so, unique_using is true
 * and using_names is a list of C strings representing names already assigned
 * to USING columns.
 *
 * When deparsing plan trees, there is always just a single item in the
 * deparse_namespace list (since a plan tree never contains Vars with
 * varlevelsup > 0).  We store the PlanState node that is the immediate
 * parent of the expression to be deparsed, as well as a list of that
 * PlanState's ancestors.  In addition, we store its outer and inner subplan
 * state nodes, as well as their plan nodes' targetlists, and the index tlist
 * if the current plan node might contain INDEX_VAR Vars.  (These fields could
 * be derived on-the-fly from the current PlanState, but it seems notationally
 * clearer to set them up as separate fields.)
 */
typedef struct
{
	List	   *rtable;			/* List of RangeTblEntry nodes */
	List	   *rtable_names;	/* Parallel list of names for RTEs */
	List	   *rtable_columns; /* Parallel list of deparse_columns structs */
	List	   *subplans;		/* List of Plan trees for SubPlans */
	List	   *ctes;			/* List of CommonTableExpr nodes */
	AppendRelInfo **appendrels; /* Array of AppendRelInfo nodes, or NULL */
	/* Workspace for column alias assignment: */
	bool		unique_using;	/* Are we making USING names globally unique */
	List	   *using_names;	/* List of assigned names for USING columns */
	/* Remaining fields are used only when deparsing a Plan tree: */
	Plan	   *plan;			/* immediate parent of current expression */
	List	   *ancestors;		/* ancestors of planstate */
	Plan	   *outer_plan;		/* outer subnode, or NULL if none */
	Plan	   *inner_plan;		/* inner subnode, or NULL if none */
	List	   *outer_tlist;	/* referent for OUTER_VAR Vars */
	List	   *inner_tlist;	/* referent for INNER_VAR Vars */
	List	   *index_tlist;	/* referent for INDEX_VAR Vars */
	/* Special namespace representing a function signature: */
	char	   *funcname;
	int			numargs;
	char	  **argnames;
} deparse_namespace;

/* Callback signature for resolve_special_varno() */
typedef void (*rsv_callback) (Node *node, deparse_context *context,
							  void *callback_arg);

/*
 * Per-relation data about column alias names.
 *
 * Selecting aliases is unreasonably complicated because of the need to dump
 * rules/views whose underlying tables may have had columns added, deleted, or
 * renamed since the query was parsed.  We must nonetheless print the rule/view
 * in a form that can be reloaded and will produce the same results as before.
 *
 * For each RTE used in the query, we must assign column aliases that are
 * unique within that RTE.  SQL does not require this of the original query,
 * but due to factors such as *-expansion we need to be able to uniquely
 * reference every column in a decompiled query.  As long as we qualify all
 * column references, per-RTE uniqueness is sufficient for that.
 *
 * However, we can't ensure per-column name uniqueness for unnamed join RTEs,
 * since they just inherit column names from their input RTEs, and we can't
 * rename the columns at the join level.  Most of the time this isn't an issue
 * because we don't need to reference the join's output columns as such; we
 * can reference the input columns instead.  That approach can fail for merged
 * JOIN USING columns, however, so when we have one of those in an unnamed
 * join, we have to make that column's alias globally unique across the whole
 * query to ensure it can be referenced unambiguously.
 *
 * Another problem is that a JOIN USING clause requires the columns to be
 * merged to have the same aliases in both input RTEs, and that no other
 * columns in those RTEs or their children conflict with the USING names.
 * To handle that, we do USING-column alias assignment in a recursive
 * traversal of the query's jointree.  When descending through a JOIN with
 * USING, we preassign the USING column names to the child columns, overriding
 * other rules for column alias assignment.  We also mark each RTE with a list
 * of all USING column names selected for joins containing that RTE, so that
 * when we assign other columns' aliases later, we can avoid conflicts.
 *
 * Another problem is that if a JOIN's input tables have had columns added or
 * deleted since the query was parsed, we must generate a column alias list
 * for the join that matches the current set of input columns --- otherwise, a
 * change in the number of columns in the left input would throw off matching
 * of aliases to columns of the right input.  Thus, positions in the printable
 * column alias list are not necessarily one-for-one with varattnos of the
 * JOIN, so we need a separate new_colnames[] array for printing purposes.
 */
typedef struct
{
	/*
	 * colnames is an array containing column aliases to use for columns that
	 * existed when the query was parsed.  Dropped columns have NULL entries.
	 * This array can be directly indexed by varattno to get a Var's name.
	 *
	 * Non-NULL entries are guaranteed unique within the RTE, *except* when
	 * this is for an unnamed JOIN RTE.  In that case we merely copy up names
	 * from the two input RTEs.
	 *
	 * During the recursive descent in set_using_names(), forcible assignment
	 * of a child RTE's column name is represented by pre-setting that element
	 * of the child's colnames array.  So at that stage, NULL entries in this
	 * array just mean that no name has been preassigned, not necessarily that
	 * the column is dropped.
	 */
	int			num_cols;		/* length of colnames[] array */
	char	  **colnames;		/* array of C strings and NULLs */

	/*
	 * new_colnames is an array containing column aliases to use for columns
	 * that would exist if the query was re-parsed against the current
	 * definitions of its base tables.  This is what to print as the column
	 * alias list for the RTE.  This array does not include dropped columns,
	 * but it will include columns added since original parsing.  Indexes in
	 * it therefore have little to do with current varattno values.  As above,
	 * entries are unique unless this is for an unnamed JOIN RTE.  (In such an
	 * RTE, we never actually print this array, but we must compute it anyway
	 * for possible use in computing column names of upper joins.) The
	 * parallel array is_new_col marks which of these columns are new since
	 * original parsing.  Entries with is_new_col false must match the
	 * non-NULL colnames entries one-for-one.
	 */
	int			num_new_cols;	/* length of new_colnames[] array */
	char	  **new_colnames;	/* array of C strings */
	bool	   *is_new_col;		/* array of bool flags */

	/* This flag tells whether we should actually print a column alias list */
	bool		printaliases;

	/* This list has all names used as USING names in joins above this RTE */
	List	   *parentUsing;	/* names assigned to parent merged columns */

	/*
	 * If this struct is for a JOIN RTE, we fill these fields during the
	 * set_using_names() pass to describe its relationship to its child RTEs.
	 *
	 * leftattnos and rightattnos are arrays with one entry per existing
	 * output column of the join (hence, indexable by join varattno).  For a
	 * simple reference to a column of the left child, leftattnos[i] is the
	 * child RTE's attno and rightattnos[i] is zero; and conversely for a
	 * column of the right child.  But for merged columns produced by JOIN
	 * USING/NATURAL JOIN, both leftattnos[i] and rightattnos[i] are nonzero.
	 * Also, if the column has been dropped, both are zero.
	 *
	 * If it's a JOIN USING, usingNames holds the alias names selected for the
	 * merged columns (these might be different from the original USING list,
	 * if we had to modify names to achieve uniqueness).
	 */
	int			leftrti;		/* rangetable index of left child */
	int			rightrti;		/* rangetable index of right child */
	int		   *leftattnos;		/* left-child varattnos of join cols, or 0 */
	int		   *rightattnos;	/* right-child varattnos of join cols, or 0 */
	List	   *usingNames;		/* names assigned to merged columns */
} deparse_columns;

/* This macro is analogous to rt_fetch(), but for deparse_columns structs */
#define deparse_columns_fetch(rangetable_index, dpns) \
	((deparse_columns *) list_nth((dpns)->rtable_columns, (rangetable_index)-1))

/*
 * Entry in set_rtable_names' hash table
 */
typedef struct
{
	char		name[NAMEDATALEN];	/* Hash key --- must be first */
	int			counter;		/* Largest addition used so far for name */
} NameHashEntry;


/* ----------
 * Local functions
 *
 * Most of these functions used to use fixed-size buffers to build their
 * results.  Now, they take an (already initialized) StringInfo object
 * as a parameter, and append their text output to its contents.
 * ----------
 */
static void set_rtable_names(deparse_namespace *dpns, List *parent_namespaces,
				 Bitmapset *rels_used);
static void set_deparse_for_query(deparse_namespace *dpns, Query *query,
					  List *parent_namespaces);
static bool has_dangerous_join_using(deparse_namespace *dpns, Node *jtnode);
static void set_using_names(deparse_namespace *dpns, Node *jtnode,
				List *parentUsing);
static void set_relation_column_names(deparse_namespace *dpns,
						  RangeTblEntry *rte,
						  deparse_columns *colinfo);
static void set_join_column_names(deparse_namespace *dpns, RangeTblEntry *rte,
					  deparse_columns *colinfo);
static bool colname_is_unique(const char *colname, deparse_namespace *dpns,
				  deparse_columns *colinfo);
static char *make_colname_unique(char *colname, deparse_namespace *dpns,
					deparse_columns *colinfo);
static void expand_colnames_array_to(deparse_columns *colinfo, int n);
static void identify_join_columns(JoinExpr *j, RangeTblEntry *jrte,
					  deparse_columns *colinfo);
static char *get_rtable_name(int rtindex, deparse_context *context);
static void set_deparse_plan(deparse_namespace *dpns, Plan *plan);
static Plan *find_recursive_union(deparse_namespace *dpns,
								  WorkTableScan *wtscan);
static void push_child_plan(deparse_namespace *dpns, Plan *plan,
				deparse_namespace *save_dpns);
static void pop_child_plan(deparse_namespace *dpns,
			   deparse_namespace *save_dpns);
static void push_ancestor_plan(deparse_namespace *dpns, ListCell *ancestor_cell,
				   deparse_namespace *save_dpns);
static void pop_ancestor_plan(deparse_namespace *dpns,
				  deparse_namespace *save_dpns);
static void get_query_def(Query *query, StringInfo buf, List *parentnamespace,
			  TupleDesc resultDesc, bool colNamesVisible,
			  int prettyFlags, int wrapColumn, int startIndent);
static void get_query_def_extended(Query *query, StringInfo buf,
				List *parentnamespace, Oid distrelid, int64 shardid,
				TupleDesc resultDesc, bool colNamesVisible,
				int prettyFlags, int wrapColumn,
				int startIndent);
static void get_values_def(List *values_lists, deparse_context *context);
static void get_with_clause(Query *query, deparse_context *context);
static void get_select_query_def(Query *query, deparse_context *context,
					 TupleDesc resultDesc, bool colNamesVisible);
static void get_insert_query_def(Query *query, deparse_context *context,
								 bool colNamesVisible);
static void get_update_query_def(Query *query, deparse_context *context,
								 bool colNamesVisible);
static void get_merge_query_def(Query *query, deparse_context *context);

static void get_update_query_targetlist_def(Query *query, List *targetList,
								deparse_context *context,
								RangeTblEntry *rte);
static void get_delete_query_def(Query *query, deparse_context *context,
								 bool colNamesVisible);
static void get_utility_query_def(Query *query, deparse_context *context);
static void get_basic_select_query(Query *query, deparse_context *context,
					   TupleDesc resultDesc, bool colNamesVisible);
static void get_target_list(List *targetList, deparse_context *context,
				TupleDesc resultDesc, bool colNamesVisible);
static void get_setop_query(Node *setOp, Query *query,
				deparse_context *context,
				TupleDesc resultDesc, bool colNamesVisible);
static Node *get_rule_sortgroupclause(Index ref, List *tlist,
						 bool force_colno,
						 deparse_context *context);
static void get_rule_groupingset(GroupingSet *gset, List *targetlist,
					 bool omit_parens, deparse_context *context);
static void get_rule_orderby(List *orderList, List *targetList,
				 bool force_colno, deparse_context *context);
static void get_rule_windowclause(Query *query, deparse_context *context);
static void get_rule_windowspec(WindowClause *wc, List *targetList,
					deparse_context *context);
static char *get_variable(Var *var, int levelsup, bool istoplevel,
			 deparse_context *context);
static void get_special_variable(Node *node, deparse_context *context,
					 void *callback_arg);
static void resolve_special_varno(Node *node, deparse_context *context,
					rsv_callback callback, void *callback_arg);
static Node *find_param_referent(Param *param, deparse_context *context,
					deparse_namespace **dpns_p, ListCell **ancestor_cell_p);
static void get_parameter(Param *param, deparse_context *context);
static const char *get_simple_binary_op_name(OpExpr *expr);
static bool isSimpleNode(Node *node, Node *parentNode, int prettyFlags);
static void appendContextKeyword(deparse_context *context, const char *str,
					 int indentBefore, int indentAfter, int indentPlus);
static void removeStringInfoSpaces(StringInfo str);
static void get_rule_expr(Node *node, deparse_context *context,
			  bool showimplicit);
static void get_rule_expr_toplevel(Node *node, deparse_context *context,
					   bool showimplicit);
static void get_rule_list_toplevel(List *lst, deparse_context *context,
								   bool showimplicit);
static void get_rule_expr_funccall(Node *node, deparse_context *context,
					   bool showimplicit);
static bool looks_like_function(Node *node);
static void get_oper_expr(OpExpr *expr, deparse_context *context);
static void get_func_expr(FuncExpr *expr, deparse_context *context,
			  bool showimplicit);
static void get_proc_expr(CallStmt *stmt, deparse_context *context,
			  bool showimplicit);
static void get_agg_expr(Aggref *aggref, deparse_context *context,
			 Aggref *original_aggref);
static void get_agg_combine_expr(Node *node, deparse_context *context,
					 void *callback_arg);
static void get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context);
static bool get_func_sql_syntax(FuncExpr *expr, deparse_context *context);
static void get_coercion_expr(Node *arg, deparse_context *context,
				  Oid resulttype, int32 resulttypmod,
				  Node *parentNode);
static void get_const_expr(Const *constval, deparse_context *context,
			   int showtype);
static void get_const_collation(Const *constval, deparse_context *context);
static void simple_quote_literal(StringInfo buf, const char *val);
static void get_sublink_expr(SubLink *sublink, deparse_context *context);
static void get_tablefunc(TableFunc *tf, deparse_context *context,
			  bool showimplicit);
static void get_from_clause(Query *query, const char *prefix,
				deparse_context *context);
static void get_from_clause_item(Node *jtnode, Query *query,
					 deparse_context *context);
static void get_column_alias_list(deparse_columns *colinfo,
					  deparse_context *context);
static void get_from_clause_coldeflist(RangeTblFunction *rtfunc,
						   deparse_columns *colinfo,
						   deparse_context *context);
static void get_tablesample_def(TableSampleClause *tablesample,
					deparse_context *context);
static void get_opclass_name(Oid opclass, Oid actual_datatype,
				 StringInfo buf);
static Node *processIndirection(Node *node, deparse_context *context);
static void printSubscripts(SubscriptingRef *aref, deparse_context *context);
static char *get_relation_name(Oid relid);
static char *generate_relation_or_shard_name(Oid relid, Oid distrelid,
				int64 shardid, List *namespaces);
static char *generate_rte_shard_name(RangeTblEntry *rangeTableEntry);
static char *generate_fragment_name(char *schemaName, char *tableName);
static char *generate_function_name(Oid funcid, int nargs,
					   List *argnames, Oid *argtypes,
					   bool has_variadic, bool *use_variadic_p,
					   ParseExprKind special_exprkind);
static List *get_insert_column_names_list(List *targetList, StringInfo buf, deparse_context *context, RangeTblEntry *rte);

#define only_marker(rte)  ((rte)->inh ? "" : "ONLY ")



/*
 * pg_get_query_def parses back one query tree, and outputs the resulting query
 * string into given buffer.
 */
void
pg_get_query_def(Query *query, StringInfo buffer)
{
	get_query_def(query, buffer, NIL, NULL, false, 0, WRAP_COLUMN_DEFAULT, 0);
}

/*
 * get_merged_argument_list merges both the IN and OUT arguments lists into one and
 * also eliminates the INOUT duplicates(present in both the lists). After merging both
 * the lists, it returns all the named-arguments in a list(mergedNamedArgList) along
 * with their types(mergedNamedArgTypes), final argument list(mergedArgumentList), and
 * the total number of arguments(totalArguments).
 */
bool
get_merged_argument_list(CallStmt *stmt, List **mergedNamedArgList,
					   Oid **mergedNamedArgTypes,
					   List **mergedArgumentList,
					   int *totalArguments)
{

	Oid  functionOid = stmt->funcexpr->funcid;
	List *namedArgList = NIL;
	List *finalArgumentList = NIL;
	Oid  *finalArgTypes;
	Oid  *argTypes = NULL;
	char *argModes = NULL;
	char **argNames = NULL;
	int  argIndex = 0;

	HeapTuple proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionOid));
	if (!HeapTupleIsValid(proctup))
	{
		elog(ERROR, "cache lookup failed for function %u", functionOid);
	}

	int defArgs = get_func_arg_info(proctup, &argTypes, &argNames, &argModes);
	ReleaseSysCache(proctup);

	if (argModes == NULL)
	{
		/* No OUT arguments */
		return false;
	}

	/*
	 * Passed arguments Includes IN, OUT, INOUT (in both the lists) and VARIADIC arguments,
	 * which means INOUT arguments are double counted.
	 */
	int numberOfArgs = list_length(stmt->funcexpr->args) + list_length(stmt->outargs);
	int totalInoutArgs = 0;

	/* Let's count INOUT arguments from the defined number of arguments */
	for (argIndex=0; argIndex < defArgs; ++argIndex)
	{
		if (argModes[argIndex] == PROARGMODE_INOUT)
			totalInoutArgs++;
	}

	/* Remove the duplicate INOUT counting */
	numberOfArgs = numberOfArgs - totalInoutArgs;
	finalArgTypes = palloc0(sizeof(Oid) * numberOfArgs);

	ListCell *inArgCell = list_head(stmt->funcexpr->args);
	ListCell *outArgCell = list_head(stmt->outargs);

	for (argIndex=0; argIndex < numberOfArgs; ++argIndex)
	{
		switch (argModes[argIndex])
		{
			case PROARGMODE_IN:
			case PROARGMODE_VARIADIC:
			{
				Node *arg = (Node *) lfirst(inArgCell);

				if (IsA(arg, NamedArgExpr))
					namedArgList = lappend(namedArgList, ((NamedArgExpr *) arg)->name);
				finalArgTypes[argIndex] = exprType(arg);
				finalArgumentList = lappend(finalArgumentList, arg);
				inArgCell = lnext(stmt->funcexpr->args, inArgCell);
				break;
			}

			case PROARGMODE_OUT:
			{
				Node *arg = (Node *) lfirst(outArgCell);

				if (IsA(arg, NamedArgExpr))
					namedArgList = lappend(namedArgList, ((NamedArgExpr *) arg)->name);
				finalArgTypes[argIndex] = exprType(arg);
				finalArgumentList = lappend(finalArgumentList, arg);
				outArgCell = lnext(stmt->outargs, outArgCell);
				break;
			}

			case PROARGMODE_INOUT:
			{
				Node *arg = (Node *) lfirst(inArgCell);

				if (IsA(arg, NamedArgExpr))
					namedArgList = lappend(namedArgList, ((NamedArgExpr *) arg)->name);
				finalArgTypes[argIndex] = exprType(arg);
				finalArgumentList = lappend(finalArgumentList, arg);
				inArgCell = lnext(stmt->funcexpr->args, inArgCell);
				outArgCell = lnext(stmt->outargs, outArgCell);
				break;
			}

			case PROARGMODE_TABLE:
			default:
			{
				elog(ERROR, "Unhandled procedure argument mode[%d]", argModes[argIndex]);
				break;
			}
		}
	}

	/*
	 * After eliminating INOUT duplicates and merging OUT arguments, we now
	 * have the final list of arguments.
	 */
	if (defArgs != list_length(finalArgumentList))
	{
		elog(ERROR, "Insufficient number of args passed[%d] for function[%s]",
											list_length(finalArgumentList),
											get_func_name(functionOid));
	}

	if (list_length(finalArgumentList) > FUNC_MAX_ARGS)
	{
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("too many arguments[%d] for function[%s]",
											list_length(finalArgumentList),
											get_func_name(functionOid))));
	}

	*mergedNamedArgList =  namedArgList;
	*mergedNamedArgTypes = finalArgTypes;
	*mergedArgumentList = finalArgumentList;
	*totalArguments = numberOfArgs;

	return true;
}

/*
 * pg_get_rule_expr deparses an expression and returns the result as a string.
 */
char *
pg_get_rule_expr(Node *expression)
{
	bool showImplicitCasts = true;
	deparse_context context;
	StringInfo buffer = makeStringInfo();

	/*
	 * Set search_path to NIL so that all objects outside of pg_catalog will be
	 * schema-prefixed. pg_catalog will be added automatically when we call
	 * PushEmptySearchPath(), since we set addCatalog to true;
	 */
	int saveNestLevel = PushEmptySearchPath();

	context.buf = buffer;
	context.namespaces = NIL;
	context.windowClause = NIL;
	context.windowTList = NIL;
	context.varprefix = false;
	context.prettyFlags = 0;
	context.wrapColumn = WRAP_COLUMN_DEFAULT;
	context.indentLevel = 0;
	context.special_exprkind = EXPR_KIND_NONE;
	context.distrelid = InvalidOid;
	context.shardid = INVALID_SHARD_ID;

	get_rule_expr(expression, &context, showImplicitCasts);

	/* revert back to original search_path */
	PopEmptySearchPath(saveNestLevel);

	return buffer->data;
}

/*
 * set_rtable_names: select RTE aliases to be used in printing a query
 *
 * We fill in dpns->rtable_names with a list of names that is one-for-one with
 * the already-filled dpns->rtable list.  Each RTE name is unique among those
 * in the new namespace plus any ancestor namespaces listed in
 * parent_namespaces.
 *
 * If rels_used isn't NULL, only RTE indexes listed in it are given aliases.
 *
 * Note that this function is only concerned with relation names, not column
 * names.
 */
static void
set_rtable_names(deparse_namespace *dpns, List *parent_namespaces,
				 Bitmapset *rels_used)
{
	HASHCTL		hash_ctl;
	HTAB	   *names_hash;
	NameHashEntry *hentry;
	bool		found;
	int			rtindex;
	ListCell   *lc;

	dpns->rtable_names = NIL;
	/* nothing more to do if empty rtable */
	if (dpns->rtable == NIL)
		return;

	/*
	 * We use a hash table to hold known names, so that this process is O(N)
	 * not O(N^2) for N names.
	 */
	hash_ctl.keysize = NAMEDATALEN;
	hash_ctl.entrysize = sizeof(NameHashEntry);
	hash_ctl.hcxt = CurrentMemoryContext;
	names_hash = hash_create("set_rtable_names names",
							 list_length(dpns->rtable),
							 &hash_ctl,
							 HASH_ELEM | HASH_STRINGS | HASH_CONTEXT);

	/* Preload the hash table with names appearing in parent_namespaces */
	foreach(lc, parent_namespaces)
	{
		deparse_namespace *olddpns = (deparse_namespace *) lfirst(lc);
		ListCell   *lc2;

		foreach(lc2, olddpns->rtable_names)
		{
			char	   *oldname = (char *) lfirst(lc2);

			if (oldname == NULL)
				continue;
			hentry = (NameHashEntry *) hash_search(names_hash,
												   oldname,
												   HASH_ENTER,
												   &found);
			/* we do not complain about duplicate names in parent namespaces */
			hentry->counter = 0;
		}
	}

	/* Now we can scan the rtable */
	rtindex = 1;
	foreach(lc, dpns->rtable)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
		char	   *refname;

		/* Just in case this takes an unreasonable amount of time ... */
		CHECK_FOR_INTERRUPTS();

		if (rels_used && !bms_is_member(rtindex, rels_used))
		{
			/* Ignore unreferenced RTE */
			refname = NULL;
		}
		else if (rte->alias)
		{
			/* If RTE has a user-defined alias, prefer that */
			refname = rte->alias->aliasname;
		}
		else if (rte->rtekind == RTE_RELATION)
		{
			/* Use the current actual name of the relation */
			refname = get_rel_name(rte->relid);
		}
		else if (rte->rtekind == RTE_JOIN)
		{
			/* Unnamed join has no refname */
			refname = NULL;
		}
		else
		{
			/* Otherwise use whatever the parser assigned */
			refname = rte->eref->aliasname;
		}

		/*
		 * If the selected name isn't unique, append digits to make it so, and
		 * make a new hash entry for it once we've got a unique name.  For a
		 * very long input name, we might have to truncate to stay within
		 * NAMEDATALEN.
		 */
		if (refname)
		{
			hentry = (NameHashEntry *) hash_search(names_hash,
												   refname,
												   HASH_ENTER,
												   &found);
			if (found)
			{
				/* Name already in use, must choose a new one */
				int			refnamelen = strlen(refname);
				char	   *modname = (char *) palloc(refnamelen + 16);
				NameHashEntry *hentry2;

				do
				{
					hentry->counter++;
					for (;;)
					{
						memcpy(modname, refname, refnamelen);
						sprintf(modname + refnamelen, "_%d", hentry->counter);
						if (strlen(modname) < NAMEDATALEN)
							break;
						/* drop chars from refname to keep all the digits */
						refnamelen = pg_mbcliplen(refname, refnamelen,
												  refnamelen - 1);
					}
					hentry2 = (NameHashEntry *) hash_search(names_hash,
															modname,
															HASH_ENTER,
															&found);
				} while (found);
				hentry2->counter = 0;	/* init new hash entry */
				refname = modname;
			}
			else
			{
				/* Name not previously used, need only initialize hentry */
				hentry->counter = 0;
			}
		}

		dpns->rtable_names = lappend(dpns->rtable_names, refname);
		rtindex++;
	}

	hash_destroy(names_hash);
}

/*
 * set_deparse_for_query: set up deparse_namespace for deparsing a Query tree
 *
 * For convenience, this is defined to initialize the deparse_namespace struct
 * from scratch.
 */
static void
set_deparse_for_query(deparse_namespace *dpns, Query *query,
					  List *parent_namespaces)
{
	ListCell   *lc;
	ListCell   *lc2;

	/* Initialize *dpns and fill rtable/ctes links */
	memset(dpns, 0, sizeof(deparse_namespace));
	dpns->rtable = query->rtable;
	dpns->subplans = NIL;
	dpns->ctes = query->cteList;
	dpns->appendrels = NULL;

	/* Assign a unique relation alias to each RTE */
	set_rtable_names(dpns, parent_namespaces, NULL);

	/* Initialize dpns->rtable_columns to contain zeroed structs */
	dpns->rtable_columns = NIL;
	while (list_length(dpns->rtable_columns) < list_length(dpns->rtable))
		dpns->rtable_columns = lappend(dpns->rtable_columns,
									   palloc0(sizeof(deparse_columns)));

	/* If it's a utility query, it won't have a jointree */
	if (query->jointree)
	{
		/* Detect whether global uniqueness of USING names is needed */
		dpns->unique_using =
			has_dangerous_join_using(dpns, (Node *) query->jointree);

		/*
		 * Select names for columns merged by USING, via a recursive pass over
		 * the query jointree.
		 */
		set_using_names(dpns, (Node *) query->jointree, NIL);
	}

	/*
	 * Now assign remaining column aliases for each RTE.  We do this in a
	 * linear scan of the rtable, so as to process RTEs whether or not they
	 * are in the jointree (we mustn't miss NEW.*, INSERT target relations,
	 * etc).  JOIN RTEs must be processed after their children, but this is
	 * okay because they appear later in the rtable list than their children
	 * (cf Asserts in identify_join_columns()).
	 */
	forboth(lc, dpns->rtable, lc2, dpns->rtable_columns)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
		deparse_columns *colinfo = (deparse_columns *) lfirst(lc2);

		if (rte->rtekind == RTE_JOIN)
			set_join_column_names(dpns, rte, colinfo);
		else
			set_relation_column_names(dpns, rte, colinfo);
	}
}

/*
 * has_dangerous_join_using: search jointree for unnamed JOIN USING
 *
 * Merged columns of a JOIN USING may act differently from either of the input
 * columns, either because they are merged with COALESCE (in a FULL JOIN) or
 * because an implicit coercion of the underlying input column is required.
 * In such a case the column must be referenced as a column of the JOIN not as
 * a column of either input.  And this is problematic if the join is unnamed
 * (alias-less): we cannot qualify the column's name with an RTE name, since
 * there is none.  (Forcibly assigning an alias to the join is not a solution,
 * since that will prevent legal references to tables below the join.)
 * To ensure that every column in the query is unambiguously referenceable,
 * we must assign such merged columns names that are globally unique across
 * the whole query, aliasing other columns out of the way as necessary.
 *
 * Because the ensuing re-aliasing is fairly damaging to the readability of
 * the query, we don't do this unless we have to.  So, we must pre-scan
 * the join tree to see if we have to, before starting set_using_names().
 */
static bool
has_dangerous_join_using(deparse_namespace *dpns, Node *jtnode)
{
	if (IsA(jtnode, RangeTblRef))
	{
		/* nothing to do here */
	}
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;
		ListCell   *lc;

		foreach(lc, f->fromlist)
		{
			if (has_dangerous_join_using(dpns, (Node *) lfirst(lc)))
				return true;
		}
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;

		/* Is it an unnamed JOIN with USING? */
		if (j->alias == NULL && j->usingClause)
		{
			/*
			 * Yes, so check each join alias var to see if any of them are not
			 * simple references to underlying columns.  If so, we have a
			 * dangerous situation and must pick unique aliases.
			 */
			RangeTblEntry *jrte = rt_fetch(j->rtindex, dpns->rtable);

			/* We need only examine the merged columns */
			for (int i = 0; i < jrte->joinmergedcols; i++)
			{
				Node	   *aliasvar = list_nth(jrte->joinaliasvars, i);

				if (!IsA(aliasvar, Var))
					return true;
			}
		}

		/* Nope, but inspect children */
		if (has_dangerous_join_using(dpns, j->larg))
			return true;
		if (has_dangerous_join_using(dpns, j->rarg))
			return true;
	}
	else
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
	return false;
}

/*
 * set_using_names: select column aliases to be used for merged USING columns
 *
 * We do this during a recursive descent of the query jointree.
 * dpns->unique_using must already be set to determine the global strategy.
 *
 * Column alias info is saved in the dpns->rtable_columns list, which is
 * assumed to be filled with pre-zeroed deparse_columns structs.
 *
 * parentUsing is a list of all USING aliases assigned in parent joins of
 * the current jointree node.  (The passed-in list must not be modified.)
 */
static void
set_using_names(deparse_namespace *dpns, Node *jtnode, List *parentUsing)
{
	if (IsA(jtnode, RangeTblRef))
	{
		/* nothing to do now */
	}
	else if (IsA(jtnode, FromExpr))
	{
		FromExpr   *f = (FromExpr *) jtnode;
		ListCell   *lc;

		foreach(lc, f->fromlist)
			set_using_names(dpns, (Node *) lfirst(lc), parentUsing);
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;
		RangeTblEntry *rte = rt_fetch(j->rtindex, dpns->rtable);
		deparse_columns *colinfo = deparse_columns_fetch(j->rtindex, dpns);
		int		   *leftattnos;
		int		   *rightattnos;
		deparse_columns *leftcolinfo;
		deparse_columns *rightcolinfo;
		int			i;
		ListCell   *lc;

		/* Get info about the shape of the join */
		identify_join_columns(j, rte, colinfo);
		leftattnos = colinfo->leftattnos;
		rightattnos = colinfo->rightattnos;

		/* Look up the not-yet-filled-in child deparse_columns structs */
		leftcolinfo = deparse_columns_fetch(colinfo->leftrti, dpns);
		rightcolinfo = deparse_columns_fetch(colinfo->rightrti, dpns);

		/*
		 * If this join is unnamed, then we cannot substitute new aliases at
		 * this level, so any name requirements pushed down to here must be
		 * pushed down again to the children.
		 */
		if (rte->alias == NULL)
		{
			for (i = 0; i < colinfo->num_cols; i++)
			{
				char	   *colname = colinfo->colnames[i];

				if (colname == NULL)
					continue;

				/* Push down to left column, unless it's a system column */
				if (leftattnos[i] > 0)
				{
					expand_colnames_array_to(leftcolinfo, leftattnos[i]);
					leftcolinfo->colnames[leftattnos[i] - 1] = colname;
				}

				/* Same on the righthand side */
				if (rightattnos[i] > 0)
				{
					expand_colnames_array_to(rightcolinfo, rightattnos[i]);
					rightcolinfo->colnames[rightattnos[i] - 1] = colname;
				}
			}
		}

		/*
		 * If there's a USING clause, select the USING column names and push
		 * those names down to the children.  We have two strategies:
		 *
		 * If dpns->unique_using is true, we force all USING names to be
		 * unique across the whole query level.  In principle we'd only need
		 * the names of dangerous USING columns to be globally unique, but to
		 * safely assign all USING names in a single pass, we have to enforce
		 * the same uniqueness rule for all of them.  However, if a USING
		 * column's name has been pushed down from the parent, we should use
		 * it as-is rather than making a uniqueness adjustment.  This is
		 * necessary when we're at an unnamed join, and it creates no risk of
		 * ambiguity.  Also, if there's a user-written output alias for a
		 * merged column, we prefer to use that rather than the input name;
		 * this simplifies the logic and seems likely to lead to less aliasing
		 * overall.
		 *
		 * If dpns->unique_using is false, we only need USING names to be
		 * unique within their own join RTE.  We still need to honor
		 * pushed-down names, though.
		 *
		 * Though significantly different in results, these two strategies are
		 * implemented by the same code, with only the difference of whether
		 * to put assigned names into dpns->using_names.
		 */
		if (j->usingClause)
		{
			/* Copy the input parentUsing list so we don't modify it */
			parentUsing = list_copy(parentUsing);

			/* USING names must correspond to the first join output columns */
			expand_colnames_array_to(colinfo, list_length(j->usingClause));
			i = 0;
			foreach(lc, j->usingClause)
			{
				char	   *colname = strVal(lfirst(lc));

				/* Assert it's a merged column */
				Assert(leftattnos[i] != 0 && rightattnos[i] != 0);

				/* Adopt passed-down name if any, else select unique name */
				if (colinfo->colnames[i] != NULL)
					colname = colinfo->colnames[i];
				else
				{
					/* Prefer user-written output alias if any */
					if (rte->alias && i < list_length(rte->alias->colnames))
						colname = strVal(list_nth(rte->alias->colnames, i));
					/* Make it appropriately unique */
					colname = make_colname_unique(colname, dpns, colinfo);
					if (dpns->unique_using)
						dpns->using_names = lappend(dpns->using_names,
													colname);
					/* Save it as output column name, too */
					colinfo->colnames[i] = colname;
				}

				/* Remember selected names for use later */
				colinfo->usingNames = lappend(colinfo->usingNames, colname);
				parentUsing = lappend(parentUsing, colname);

				/* Push down to left column, unless it's a system column */
				if (leftattnos[i] > 0)
				{
					expand_colnames_array_to(leftcolinfo, leftattnos[i]);
					leftcolinfo->colnames[leftattnos[i] - 1] = colname;
				}

				/* Same on the righthand side */
				if (rightattnos[i] > 0)
				{
					expand_colnames_array_to(rightcolinfo, rightattnos[i]);
					rightcolinfo->colnames[rightattnos[i] - 1] = colname;
				}

				i++;
			}
		}

		/* Mark child deparse_columns structs with correct parentUsing info */
		leftcolinfo->parentUsing = parentUsing;
		rightcolinfo->parentUsing = parentUsing;

		/* Now recursively assign USING column names in children */
		set_using_names(dpns, j->larg, parentUsing);
		set_using_names(dpns, j->rarg, parentUsing);
	}
	else
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
}

/*
 * set_relation_column_names: select column aliases for a non-join RTE
 *
 * Column alias info is saved in *colinfo, which is assumed to be pre-zeroed.
 * If any colnames entries are already filled in, those override local
 * choices.
 */
static void
set_relation_column_names(deparse_namespace *dpns, RangeTblEntry *rte,
						  deparse_columns *colinfo)
{
	int			ncolumns;
	char	  **real_colnames;
	bool		changed_any;
	bool 		has_anonymous;
	int			noldcolumns;
	int			i;
	int			j;

	/*
	 * Construct an array of the current "real" column names of the RTE.
	 * real_colnames[] will be indexed by physical column number, with NULL
	 * entries for dropped columns.
	 */
	if (rte->rtekind == RTE_RELATION ||
        GetRangeTblKind(rte) == CITUS_RTE_SHARD)
	{
		/* Relation --- look to the system catalogs for up-to-date info */
		Relation	rel;
		TupleDesc	tupdesc;

		rel = relation_open(rte->relid, AccessShareLock);
		tupdesc = RelationGetDescr(rel);

		ncolumns = tupdesc->natts;
		real_colnames = (char **) palloc(ncolumns * sizeof(char *));

		for (i = 0; i < ncolumns; i++)
		{
			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);

			if (attr->attisdropped)
				real_colnames[i] = NULL;
			else
				real_colnames[i] = pstrdup(NameStr(attr->attname));
		}
		relation_close(rel, AccessShareLock);
	}
	else
	{
		/* Otherwise get the column names from eref or expandRTE() */
		List	   *colnames;
		ListCell   *lc;

		/*
		 * Functions returning composites have the annoying property that some
		 * of the composite type's columns might have been dropped since the
		 * query was parsed.  If possible, use expandRTE() to handle that
		 * case, since it has the tedious logic needed to find out about
		 * dropped columns.  However, if we're explaining a plan, then we
		 * don't have rte->functions because the planner thinks that won't be
		 * needed later, and that breaks expandRTE().  So in that case we have
		 * to rely on rte->eref, which may lead us to report a dropped
		 * column's old name; that seems close enough for EXPLAIN's purposes.
		 *
		 * For non-RELATION, non-FUNCTION RTEs, we can just look at rte->eref,
		 * which should be sufficiently up-to-date: no other RTE types can
		 * have columns get dropped from under them after parsing.
		 */
		if (rte->rtekind == RTE_FUNCTION && rte->functions != NIL)
		{
			/* Since we're not creating Vars, rtindex etc. don't matter */
			expandRTE(rte, 1, 0, -1, true /* include dropped */ ,
					  &colnames, NULL);
		}
		else
			colnames = rte->eref->colnames;

		ncolumns = list_length(colnames);
		real_colnames = (char **) palloc(ncolumns * sizeof(char *));

		i = 0;
		foreach(lc, colnames)
		{
			/*
			 * If the column name we find here is an empty string, then it's a
			 * dropped column, so change to NULL.
			 */
			char	   *cname = strVal(lfirst(lc));

			if (cname[0] == '\0')
				cname = NULL;
			real_colnames[i] = cname;
			i++;
		}
	}

	/*
	 * Ensure colinfo->colnames has a slot for each column.  (It could be long
	 * enough already, if we pushed down a name for the last column.)  Note:
	 * it's possible that there are now more columns than there were when the
	 * query was parsed, ie colnames could be longer than rte->eref->colnames.
	 * We must assign unique aliases to the new columns too, else there could
	 * be unresolved conflicts when the view/rule is reloaded.
	 */
	expand_colnames_array_to(colinfo, ncolumns);
	Assert(colinfo->num_cols == ncolumns);

	/*
	 * Make sufficiently large new_colnames and is_new_col arrays, too.
	 *
	 * Note: because we leave colinfo->num_new_cols zero until after the loop,
	 * colname_is_unique will not consult that array, which is fine because it
	 * would only be duplicate effort.
	 */
	colinfo->new_colnames = (char **) palloc(ncolumns * sizeof(char *));
	colinfo->is_new_col = (bool *) palloc(ncolumns * sizeof(bool));

	/*
	 * Scan the columns, select a unique alias for each one, and store it in
	 * colinfo->colnames and colinfo->new_colnames.  The former array has NULL
	 * entries for dropped columns, the latter omits them.  Also mark
	 * new_colnames entries as to whether they are new since parse time; this
	 * is the case for entries beyond the length of rte->eref->colnames.
	 */
	noldcolumns = list_length(rte->eref->colnames);
	changed_any = false;
	has_anonymous = false;
	j = 0;
	for (i = 0; i < ncolumns; i++)
	{
		char	   *real_colname = real_colnames[i];
		char	   *colname = colinfo->colnames[i];

		/* Skip dropped columns */
		if (real_colname == NULL)
		{
			Assert(colname == NULL);	/* colnames[i] is already NULL */
			continue;
		}

		/* If alias already assigned, that's what to use */
		if (colname == NULL)
		{
			/* If user wrote an alias, prefer that over real column name */
			if (rte->alias && i < list_length(rte->alias->colnames))
				colname = strVal(list_nth(rte->alias->colnames, i));
			else
				colname = real_colname;

			/* Unique-ify and insert into colinfo */
			colname = make_colname_unique(colname, dpns, colinfo);

			colinfo->colnames[i] = colname;
		}

		/* Put names of non-dropped columns in new_colnames[] too */
		colinfo->new_colnames[j] = colname;
		/* And mark them as new or not */
		colinfo->is_new_col[j] = (i >= noldcolumns);
		j++;

		/* Remember if any assigned aliases differ from "real" name */
		if (!changed_any && strcmp(colname, real_colname) != 0)
			changed_any = true;

		/*
		 * Remember if there is a reference to an anonymous column as named by
		 * char * FigureColname(Node *node)
		 */
		if (!has_anonymous && strcmp(real_colname, "?column?") == 0)
			has_anonymous = true;
	}

	/*
	 * Set correct length for new_colnames[] array.  (Note: if columns have
	 * been added, colinfo->num_cols includes them, which is not really quite
	 * right but is harmless, since any new columns must be at the end where
	 * they won't affect varattnos of pre-existing columns.)
	 */
	colinfo->num_new_cols = j;

	/*
	 * For a relation RTE, we need only print the alias column names if any
	 * are different from the underlying "real" names.  For a function RTE,
	 * always emit a complete column alias list; this is to protect against
	 * possible instability of the default column names (eg, from altering
	 * parameter names).  For tablefunc RTEs, we never print aliases, because
	 * the column names are part of the clause itself.  For other RTE types,
	 * print if we changed anything OR if there were user-written column
	 * aliases (since the latter would be part of the underlying "reality").
	 */
	if (rte->rtekind == RTE_RELATION)
		colinfo->printaliases = changed_any;
	else if (rte->rtekind == RTE_FUNCTION)
		colinfo->printaliases = true;
	else if (rte->rtekind == RTE_TABLEFUNC)
		colinfo->printaliases = false;
	else if (rte->alias && rte->alias->colnames != NIL)
		colinfo->printaliases = true;
	else
		colinfo->printaliases = changed_any || has_anonymous;
}

/*
 * set_join_column_names: select column aliases for a join RTE
 *
 * Column alias info is saved in *colinfo, which is assumed to be pre-zeroed.
 * If any colnames entries are already filled in, those override local
 * choices.  Also, names for USING columns were already chosen by
 * set_using_names().  We further expect that column alias selection has been
 * completed for both input RTEs.
 */
static void
set_join_column_names(deparse_namespace *dpns, RangeTblEntry *rte,
					  deparse_columns *colinfo)
{
	deparse_columns *leftcolinfo;
	deparse_columns *rightcolinfo;
	bool		changed_any;
	int			noldcolumns;
	int			nnewcolumns;
	Bitmapset  *leftmerged = NULL;
	Bitmapset  *rightmerged = NULL;
	int			i;
	int			j;
	int			ic;
	int			jc;

	/* Look up the previously-filled-in child deparse_columns structs */
	leftcolinfo = deparse_columns_fetch(colinfo->leftrti, dpns);
	rightcolinfo = deparse_columns_fetch(colinfo->rightrti, dpns);

	/*
	 * Ensure colinfo->colnames has a slot for each column.  (It could be long
	 * enough already, if we pushed down a name for the last column.)  Note:
	 * it's possible that one or both inputs now have more columns than there
	 * were when the query was parsed, but we'll deal with that below.  We
	 * only need entries in colnames for pre-existing columns.
	 */
	noldcolumns = list_length(rte->eref->colnames);
	expand_colnames_array_to(colinfo, noldcolumns);
	Assert(colinfo->num_cols == noldcolumns);

	/*
	 * Scan the join output columns, select an alias for each one, and store
	 * it in colinfo->colnames.  If there are USING columns, set_using_names()
	 * already selected their names, so we can start the loop at the first
	 * non-merged column.
	 */
	changed_any = false;
	for (i = list_length(colinfo->usingNames); i < noldcolumns; i++)
	{
		char	   *colname = colinfo->colnames[i];
		char	   *real_colname;

		/* Join column must refer to at least one input column */
		Assert(colinfo->leftattnos[i] != 0 || colinfo->rightattnos[i] != 0);

		/* Get the child column name */
		if (colinfo->leftattnos[i] > 0)
			real_colname = leftcolinfo->colnames[colinfo->leftattnos[i] - 1];
		else if (colinfo->rightattnos[i] > 0)
			real_colname = rightcolinfo->colnames[colinfo->rightattnos[i] - 1];
		else
		{
			/* We're joining system columns --- use eref name */
			real_colname = strVal(list_nth(rte->eref->colnames, i));
		}
			/* If child col has been dropped, no need to assign a join colname */
		if (real_colname == NULL)
		{
			colinfo->colnames[i] = NULL;
			continue;
		}

		/* In an unnamed join, just report child column names as-is */
		if (rte->alias == NULL)
		{
			colinfo->colnames[i] = real_colname;
			continue;
		}

		/* If alias already assigned, that's what to use */
		if (colname == NULL)
		{
			/* If user wrote an alias, prefer that over real column name */
			if (rte->alias && i < list_length(rte->alias->colnames))
				colname = strVal(list_nth(rte->alias->colnames, i));
			else
				colname = real_colname;

			/* Unique-ify and insert into colinfo */
			colname = make_colname_unique(colname, dpns, colinfo);

			colinfo->colnames[i] = colname;
		}

		/* Remember if any assigned aliases differ from "real" name */
		if (!changed_any && strcmp(colname, real_colname) != 0)
			changed_any = true;
	}

	/*
	 * Calculate number of columns the join would have if it were re-parsed
	 * now, and create storage for the new_colnames and is_new_col arrays.
	 *
	 * Note: colname_is_unique will be consulting new_colnames[] during the
	 * loops below, so its not-yet-filled entries must be zeroes.
	 */
	nnewcolumns = leftcolinfo->num_new_cols + rightcolinfo->num_new_cols -
		list_length(colinfo->usingNames);
	colinfo->num_new_cols = nnewcolumns;
	colinfo->new_colnames = (char **) palloc0(nnewcolumns * sizeof(char *));
	colinfo->is_new_col = (bool *) palloc0(nnewcolumns * sizeof(bool));

	/*
	 * Generating the new_colnames array is a bit tricky since any new columns
	 * added since parse time must be inserted in the right places.  This code
	 * must match the parser, which will order a join's columns as merged
	 * columns first (in USING-clause order), then non-merged columns from the
	 * left input (in attnum order), then non-merged columns from the right
	 * input (ditto).  If one of the inputs is itself a join, its columns will
	 * be ordered according to the same rule, which means newly-added columns
	 * might not be at the end.  We can figure out what's what by consulting
	 * the leftattnos and rightattnos arrays plus the input is_new_col arrays.
	 *
	 * In these loops, i indexes leftattnos/rightattnos (so it's join varattno
	 * less one), j indexes new_colnames/is_new_col, and ic/jc have similar
	 * meanings for the current child RTE.
	 */

	/* Handle merged columns; they are first and can't be new */
	i = j = 0;
	while (i < noldcolumns &&
		   colinfo->leftattnos[i] != 0 &&
		   colinfo->rightattnos[i] != 0)
	{
		/* column name is already determined and known unique */
		colinfo->new_colnames[j] = colinfo->colnames[i];
		colinfo->is_new_col[j] = false;

		/* build bitmapsets of child attnums of merged columns */
		if (colinfo->leftattnos[i] > 0)
			leftmerged = bms_add_member(leftmerged, colinfo->leftattnos[i]);
		if (colinfo->rightattnos[i] > 0)
			rightmerged = bms_add_member(rightmerged, colinfo->rightattnos[i]);

		i++, j++;
	}

	/* Handle non-merged left-child columns */
	ic = 0;
	for (jc = 0; jc < leftcolinfo->num_new_cols; jc++)
	{
		char	   *child_colname = leftcolinfo->new_colnames[jc];

		if (!leftcolinfo->is_new_col[jc])
		{
			/* Advance ic to next non-dropped old column of left child */
			while (ic < leftcolinfo->num_cols &&
				   leftcolinfo->colnames[ic] == NULL)
				ic++;
			Assert(ic < leftcolinfo->num_cols);
			ic++;
			/* If it is a merged column, we already processed it */
			if (bms_is_member(ic, leftmerged))
				continue;
			/* Else, advance i to the corresponding existing join column */
			while (i < colinfo->num_cols &&
				   colinfo->colnames[i] == NULL)
				i++;
			Assert(i < colinfo->num_cols);
			Assert(ic == colinfo->leftattnos[i]);
			/* Use the already-assigned name of this column */
			colinfo->new_colnames[j] = colinfo->colnames[i];
			i++;
		}
		else
		{
			/*
			 * Unique-ify the new child column name and assign, unless we're
			 * in an unnamed join, in which case just copy
			 */
			if (rte->alias != NULL)
			{
				colinfo->new_colnames[j] =
					make_colname_unique(child_colname, dpns, colinfo);
				if (!changed_any &&
					strcmp(colinfo->new_colnames[j], child_colname) != 0)
					changed_any = true;
			}
			else
				colinfo->new_colnames[j] = child_colname;
		}

		colinfo->is_new_col[j] = leftcolinfo->is_new_col[jc];
		j++;
	}

	/* Handle non-merged right-child columns in exactly the same way */
	ic = 0;
	for (jc = 0; jc < rightcolinfo->num_new_cols; jc++)
	{
		char	   *child_colname = rightcolinfo->new_colnames[jc];

		if (!rightcolinfo->is_new_col[jc])
		{
			/* Advance ic to next non-dropped old column of right child */
			while (ic < rightcolinfo->num_cols &&
				   rightcolinfo->colnames[ic] == NULL)
				ic++;
			Assert(ic < rightcolinfo->num_cols);
			ic++;
			/* If it is a merged column, we already processed it */
			if (bms_is_member(ic, rightmerged))
				continue;
			/* Else, advance i to the corresponding existing join column */
			while (i < colinfo->num_cols &&
				   colinfo->colnames[i] == NULL)
				i++;
			Assert(i < colinfo->num_cols);
			Assert(ic == colinfo->rightattnos[i]);
			/* Use the already-assigned name of this column */
			colinfo->new_colnames[j] = colinfo->colnames[i];
			i++;
		}
		else
		{
			/*
			 * Unique-ify the new child column name and assign, unless we're
			 * in an unnamed join, in which case just copy
			 */
			if (rte->alias != NULL)
			{
				colinfo->new_colnames[j] =
					make_colname_unique(child_colname, dpns, colinfo);
				if (!changed_any &&
					strcmp(colinfo->new_colnames[j], child_colname) != 0)
					changed_any = true;
			}
			else
				colinfo->new_colnames[j] = child_colname;
		}

		colinfo->is_new_col[j] = rightcolinfo->is_new_col[jc];
		j++;
	}

	/* Assert we processed the right number of columns */
#ifdef USE_ASSERT_CHECKING
	for (int col_index = 0; col_index < colinfo->num_cols; col_index++)
	{
		/*
		 * In the above processing-loops, "i" advances only if
		 * the column is not new, check if this is a new column.
		 */
		if (colinfo->is_new_col[col_index])
			i++;
	}
	Assert(i == colinfo->num_cols);
	Assert(j == nnewcolumns);
#endif

	/*
	 * For a named join, print column aliases if we changed any from the child
	 * names.  Unnamed joins cannot print aliases.
	 */
	if (rte->alias != NULL)
		colinfo->printaliases = changed_any;
	else
		colinfo->printaliases = false;
}

/*
 * colname_is_unique: is colname distinct from already-chosen column names?
 *
 * dpns is query-wide info, colinfo is for the column's RTE
 */
static bool
colname_is_unique(const char *colname, deparse_namespace *dpns,
				  deparse_columns *colinfo)
{
	int			i;
	ListCell   *lc;

	/* Check against already-assigned column aliases within RTE */
	for (i = 0; i < colinfo->num_cols; i++)
	{
		char	   *oldname = colinfo->colnames[i];

		if (oldname && strcmp(oldname, colname) == 0)
			return false;
	}

	/*
	 * If we're building a new_colnames array, check that too (this will be
	 * partially but not completely redundant with the previous checks)
	 */
	for (i = 0; i < colinfo->num_new_cols; i++)
	{
		char	   *oldname = colinfo->new_colnames[i];

		if (oldname && strcmp(oldname, colname) == 0)
			return false;
	}

	/* Also check against USING-column names that must be globally unique */
	foreach(lc, dpns->using_names)
	{
		char	   *oldname = (char *) lfirst(lc);

		if (strcmp(oldname, colname) == 0)
			return false;
	}

	/* Also check against names already assigned for parent-join USING cols */
	foreach(lc, colinfo->parentUsing)
	{
		char	   *oldname = (char *) lfirst(lc);

		if (strcmp(oldname, colname) == 0)
			return false;
	}

	return true;
}

/*
 * make_colname_unique: modify colname if necessary to make it unique
 *
 * dpns is query-wide info, colinfo is for the column's RTE
 */
static char *
make_colname_unique(char *colname, deparse_namespace *dpns,
					deparse_columns *colinfo)
{
	/*
	 * If the selected name isn't unique, append digits to make it so.  For a
	 * very long input name, we might have to truncate to stay within
	 * NAMEDATALEN.
	 */
	if (!colname_is_unique(colname, dpns, colinfo))
	{
		int			colnamelen = strlen(colname);
		char	   *modname = (char *) palloc(colnamelen + 16);
		int			i = 0;

		do
		{
			i++;
			for (;;)
			{
				memcpy(modname, colname, colnamelen);
				sprintf(modname + colnamelen, "_%d", i);
				if (strlen(modname) < NAMEDATALEN)
					break;
				/* drop chars from colname to keep all the digits */
				colnamelen = pg_mbcliplen(colname, colnamelen,
										  colnamelen - 1);
			}
		} while (!colname_is_unique(modname, dpns, colinfo));
		colname = modname;
	}
	return colname;
}

/*
 * expand_colnames_array_to: make colinfo->colnames at least n items long
 *
 * Any added array entries are initialized to zero.
 */
static void
expand_colnames_array_to(deparse_columns *colinfo, int n)
{
	if (n > colinfo->num_cols)
	{
		if (colinfo->colnames == NULL)
			colinfo->colnames = (char **) palloc0(n * sizeof(char *));
		else
		{
			colinfo->colnames = (char **) repalloc(colinfo->colnames,
												   n * sizeof(char *));
			memset(colinfo->colnames + colinfo->num_cols, 0,
				   (n - colinfo->num_cols) * sizeof(char *));
		}
		colinfo->num_cols = n;
	}
}

/*
 * identify_join_columns: figure out where columns of a join come from
 *
 * Fills the join-specific fields of the colinfo struct, except for
 * usingNames which is filled later.
 */
static void
identify_join_columns(JoinExpr *j, RangeTblEntry *jrte,
					  deparse_columns *colinfo)
{
	int			numjoincols;
	int			jcolno;
	int			rcolno;
	ListCell   *lc;

	/* Extract left/right child RT indexes */
	if (IsA(j->larg, RangeTblRef))
		colinfo->leftrti = ((RangeTblRef *) j->larg)->rtindex;
	else if (IsA(j->larg, JoinExpr))
		colinfo->leftrti = ((JoinExpr *) j->larg)->rtindex;
	else
		elog(ERROR, "unrecognized node type in jointree: %d",
			 (int) nodeTag(j->larg));
	if (IsA(j->rarg, RangeTblRef))
		colinfo->rightrti = ((RangeTblRef *) j->rarg)->rtindex;
	else if (IsA(j->rarg, JoinExpr))
		colinfo->rightrti = ((JoinExpr *) j->rarg)->rtindex;
	else
		elog(ERROR, "unrecognized node type in jointree: %d",
			 (int) nodeTag(j->rarg));

	/* Assert children will be processed earlier than join in second pass */
	Assert(colinfo->leftrti < j->rtindex);
	Assert(colinfo->rightrti < j->rtindex);

	/* Initialize result arrays with zeroes */
	numjoincols = list_length(jrte->joinaliasvars);
	Assert(numjoincols == list_length(jrte->eref->colnames));
	colinfo->leftattnos = (int *) palloc0(numjoincols * sizeof(int));
	colinfo->rightattnos = (int *) palloc0(numjoincols * sizeof(int));

	/*
	 * Deconstruct RTE's joinleftcols/joinrightcols into desired format.
	 * Recall that the column(s) merged due to USING are the first column(s)
	 * of the join output.  We need not do anything special while scanning
	 * joinleftcols, but while scanning joinrightcols we must distinguish
	 * merged from unmerged columns.
	 */
	jcolno = 0;
	foreach(lc, jrte->joinleftcols)
	{
		int			leftattno = lfirst_int(lc);

		colinfo->leftattnos[jcolno++] = leftattno;
	}
	rcolno = 0;
	foreach(lc, jrte->joinrightcols)
	{
		int			rightattno = lfirst_int(lc);

		if (rcolno < jrte->joinmergedcols)	/* merged column? */
			colinfo->rightattnos[rcolno] = rightattno;
		else
			colinfo->rightattnos[jcolno++] = rightattno;
		rcolno++;
	}
	Assert(jcolno == numjoincols);
}

/*
 * get_rtable_name: convenience function to get a previously assigned RTE alias
 *
 * The RTE must belong to the topmost namespace level in "context".
 */
static char *
get_rtable_name(int rtindex, deparse_context *context)
{
	deparse_namespace *dpns = (deparse_namespace *) linitial(context->namespaces);

	Assert(rtindex > 0 && rtindex <= list_length(dpns->rtable_names));
	return (char *) list_nth(dpns->rtable_names, rtindex - 1);
}

/*
 * set_deparse_plan: set up deparse_namespace to parse subexpressions
 * of a given Plan node
 *
 * This sets the plan, outer_planstate, inner_planstate, outer_tlist,
 * inner_tlist, and index_tlist fields.  Caller is responsible for adjusting
 * the ancestors list if necessary.  Note that the rtable and ctes fields do
 * not need to change when shifting attention to different plan nodes in a
 * single plan tree.
 */
static void
set_deparse_plan(deparse_namespace *dpns, Plan *plan)
{
	dpns->plan = plan;

	/*
	 * We special-case Append and MergeAppend to pretend that the first child
	 * plan is the OUTER referent; we have to interpret OUTER Vars in their
	 * tlists according to one of the children, and the first one is the most
	 * natural choice.
	 */
	if (IsA(plan, Append))
		dpns->outer_plan = linitial(((Append *) plan)->appendplans);
	else if (IsA(plan, MergeAppend))
		dpns->outer_plan = linitial(((MergeAppend *) plan)->mergeplans);
	else
		dpns->outer_plan = outerPlan(plan);

	if (dpns->outer_plan)
		dpns->outer_tlist = dpns->outer_plan->targetlist;
	else
		dpns->outer_tlist = NIL;

	/*
	 * For a SubqueryScan, pretend the subplan is INNER referent.  (We don't
	 * use OUTER because that could someday conflict with the normal meaning.)
	 * Likewise, for a CteScan, pretend the subquery's plan is INNER referent.
     * For a WorkTableScan, locate the parent RecursiveUnion plan node and use
     * that as INNER referent.
     *
     * For MERGE, make the inner tlist point to the merge source tlist, which
	 * is same as the targetlist that the ModifyTable's source plan provides.
	 * For ON CONFLICT .. UPDATE we just need the inner tlist to point to the
	 * excluded expression's tlist. (Similar to the SubqueryScan we don't want
	 * to reuse OUTER, it's used for RETURNING in some modify table cases,
	 * although not INSERT .. CONFLICT).
	 */
	if (IsA(plan, SubqueryScan))
		dpns->inner_plan = ((SubqueryScan *) plan)->subplan;
	else if (IsA(plan, CteScan))
		dpns->inner_plan = list_nth(dpns->subplans,
									((CteScan *) plan)->ctePlanId - 1);
    else if (IsA(plan, WorkTableScan))
		dpns->inner_plan = find_recursive_union(dpns,
												(WorkTableScan *) plan);
	else if (IsA(plan, ModifyTable))
		dpns->inner_plan = plan;
	else
		dpns->inner_plan = innerPlan(plan);

	if (IsA(plan, ModifyTable))
	{
		if (((ModifyTable *) plan)->operation == CMD_MERGE)
			dpns->inner_tlist = dpns->outer_tlist;
		else
			dpns->inner_tlist = ((ModifyTable *) plan)->exclRelTlist;
	}
	else if (dpns->inner_plan)
		dpns->inner_tlist = dpns->inner_plan->targetlist;
	else
		dpns->inner_tlist = NIL;

	/* Set up referent for INDEX_VAR Vars, if needed */
	if (IsA(plan, IndexOnlyScan))
		dpns->index_tlist = ((IndexOnlyScan *) plan)->indextlist;
	else if (IsA(plan, ForeignScan))
		dpns->index_tlist = ((ForeignScan *) plan)->fdw_scan_tlist;
	else if (IsA(plan, CustomScan))
		dpns->index_tlist = ((CustomScan *) plan)->custom_scan_tlist;
	else
		dpns->index_tlist = NIL;
}

/*
 * Locate the ancestor plan node that is the RecursiveUnion generating
 * the WorkTableScan's work table.  We can match on wtParam, since that
 * should be unique within the plan tree.
 */
static Plan *
find_recursive_union(deparse_namespace *dpns, WorkTableScan *wtscan)
{
	ListCell   *lc;

	foreach(lc, dpns->ancestors)
	{
		Plan	   *ancestor = (Plan *) lfirst(lc);

		if (IsA(ancestor, RecursiveUnion) &&
			((RecursiveUnion *) ancestor)->wtParam == wtscan->wtParam)
			return ancestor;
	}
	elog(ERROR, "could not find RecursiveUnion for WorkTableScan with wtParam %d",
		 wtscan->wtParam);
	return NULL;
}

/*
 * push_child_plan: temporarily transfer deparsing attention to a child plan
 *
 * When expanding an OUTER_VAR or INNER_VAR reference, we must adjust the
 * deparse context in case the referenced expression itself uses
 * OUTER_VAR/INNER_VAR.  We modify the top stack entry in-place to avoid
 * affecting levelsup issues (although in a Plan tree there really shouldn't
 * be any).
 *
 * Caller must provide a local deparse_namespace variable to save the
 * previous state for pop_child_plan.
 */
static void
push_child_plan(deparse_namespace *dpns, Plan *plan,
				deparse_namespace *save_dpns)
{
	/* Save state for restoration later */
	*save_dpns = *dpns;

	/* Link current plan node into ancestors list */
	dpns->ancestors = lcons(dpns->plan, dpns->ancestors);

	/* Set attention on selected child */
	set_deparse_plan(dpns, plan);
}

/*
 * pop_child_plan: undo the effects of push_child_plan
 */
static void
pop_child_plan(deparse_namespace *dpns, deparse_namespace *save_dpns)
{
	List	   *ancestors;

	/* Get rid of ancestors list cell added by push_child_plan */
	ancestors = list_delete_first(dpns->ancestors);

	/* Restore fields changed by push_child_plan */
	*dpns = *save_dpns;

	/* Make sure dpns->ancestors is right (may be unnecessary) */
	dpns->ancestors = ancestors;
}

/*
 * push_ancestor_plan: temporarily transfer deparsing attention to an
 * ancestor plan
 *
 * When expanding a Param reference, we must adjust the deparse context
 * to match the plan node that contains the expression being printed;
 * otherwise we'd fail if that expression itself contains a Param or
 * OUTER_VAR/INNER_VAR/INDEX_VAR variable.
 *
 * The target ancestor is conveniently identified by the ListCell holding it
 * in dpns->ancestors.
 *
 * Caller must provide a local deparse_namespace variable to save the
 * previous state for pop_ancestor_plan.
 */
static void
push_ancestor_plan(deparse_namespace *dpns, ListCell *ancestor_cell,
				   deparse_namespace *save_dpns)
{
	Plan	   *plan = (Plan *) lfirst(ancestor_cell);

	/* Save state for restoration later */
	*save_dpns = *dpns;

	/* Build a new ancestor list with just this node's ancestors */
	dpns->ancestors =
		list_copy_tail(dpns->ancestors,
					   list_cell_number(dpns->ancestors, ancestor_cell) + 1);

	/* Set attention on selected ancestor */
	set_deparse_plan(dpns, plan);
}

/*
 * pop_ancestor_plan: undo the effects of push_ancestor_plan
 */
static void
pop_ancestor_plan(deparse_namespace *dpns, deparse_namespace *save_dpns)
{
	/* Free the ancestor list made in push_ancestor_plan */
	list_free(dpns->ancestors);

	/* Restore fields changed by push_ancestor_plan */
	*dpns = *save_dpns;
}

/* ----------
 * deparse_shard_query		- Parse back a query for execution on a shard
 *
 * Builds an SQL string to perform the provided query on a specific shard and
 * places this string into the provided buffer.
 * ----------
 */
void
deparse_shard_query(Query *query, Oid distrelid, int64 shardid,
					StringInfo buffer)
{
	get_query_def_extended(query, buffer, NIL, distrelid, shardid, NULL,
	                       false,
						   0, WRAP_COLUMN_DEFAULT, 0);
}

/* ----------
 * get_query_def			- Parse back one query parsetree
 *
 * query: parsetree to be displayed
 * buf: output text is appended to buf
 * parentnamespace: list (initially empty) of outer-level deparse_namespace's
 * resultDesc: if not NULL, the output tuple descriptor for the view
 *		represented by a SELECT query.  We use the column names from it
 *		to label SELECT output columns, in preference to names in the query
 * colNamesVisible: true if the surrounding context cares about the output
 *		column names at all (as, for example, an EXISTS() context does not);
 *		when false, we can suppress dummy column labels such as "?column?"
 * prettyFlags: bitmask of PRETTYFLAG_XXX options
 * wrapColumn: maximum line length, or -1 to disable wrapping
 * startIndent: initial indentation amount
 * ----------
 */
static void
get_query_def(Query *query, StringInfo buf, List *parentnamespace,
			  TupleDesc resultDesc, bool colNamesVisible,
			  int prettyFlags, int wrapColumn, int startIndent)
{
	get_query_def_extended(query, buf, parentnamespace, InvalidOid, 0, resultDesc,
	                       colNamesVisible,
						   prettyFlags, wrapColumn, startIndent);
}

/* ----------
 * get_query_def_extended		- Parse back one query parsetree, optionally
 * 								  with extension using a shard identifier.
 *
 * If distrelid is valid and shardid is positive, the provided shardid is added
 * any time the provided relid is deparsed, so that the query may be executed
 * on a placement for the given shard.
 * ----------
 */
static void
get_query_def_extended(Query *query, StringInfo buf, List *parentnamespace,
					   Oid distrelid, int64 shardid, TupleDesc resultDesc,
					   bool colNamesVisible,
					   int prettyFlags, int wrapColumn, int startIndent)
{
	deparse_context context;
	deparse_namespace dpns;

	/* Guard against excessively long or deeply-nested queries */
	CHECK_FOR_INTERRUPTS();
	check_stack_depth();

	/*
	 * Before we begin to examine the query, acquire locks on referenced
	 * relations, and fix up deleted columns in JOIN RTEs.  This ensures
	 * consistent results.  Note we assume it's OK to scribble on the passed
	 * querytree!
	 *
	 * We are only deparsing the query (we are not about to execute it), so we
	 * only need AccessShareLock on the relations it mentions.
	 */
	AcquireRewriteLocks(query, false, false);

	/*
	 * Set search_path to NIL so that all objects outside of pg_catalog will be
	 * schema-prefixed. pg_catalog will be added automatically when we call
	 * PushEmptySearchPath().
	 */
	int saveNestLevel = PushEmptySearchPath();

	context.buf = buf;
	context.namespaces = lcons(&dpns, list_copy(parentnamespace));
	context.windowClause = NIL;
	context.windowTList = NIL;
	context.varprefix = (parentnamespace != NIL ||
						 list_length(query->rtable) != 1);
	context.prettyFlags = prettyFlags;
	context.wrapColumn = wrapColumn;
	context.indentLevel = startIndent;
	context.special_exprkind = EXPR_KIND_NONE;
	context.appendparents = NULL;
	context.distrelid = distrelid;
	context.shardid = shardid;

	set_deparse_for_query(&dpns, query, parentnamespace);

	switch (query->commandType)
	{
		case CMD_SELECT:
			get_select_query_def(query, &context, resultDesc, colNamesVisible);
			break;

		case CMD_UPDATE:
			get_update_query_def(query, &context, colNamesVisible);
			break;

		case CMD_INSERT:
			get_insert_query_def(query, &context, colNamesVisible);
			break;

		case CMD_DELETE:
			get_delete_query_def(query, &context, colNamesVisible);
			break;

		case CMD_MERGE:
			get_merge_query_def(query, &context);
			break;

		case CMD_NOTHING:
			appendStringInfoString(buf, "NOTHING");
			break;

		case CMD_UTILITY:
			get_utility_query_def(query, &context);
			break;

		default:
			elog(ERROR, "unrecognized query command type: %d",
				 query->commandType);
			break;
	}

	/* revert back to original search_path */
	PopEmptySearchPath(saveNestLevel);
}

/* ----------
 * get_values_def			- Parse back a VALUES list
 * ----------
 */
static void
get_values_def(List *values_lists, deparse_context *context)
{
	StringInfo	buf = context->buf;
	bool		first_list = true;
	ListCell   *vtl;

	appendStringInfoString(buf, "VALUES ");

	foreach(vtl, values_lists)
	{
		List	   *sublist = (List *) lfirst(vtl);
		bool		first_col = true;
		ListCell   *lc;

		if (first_list)
			first_list = false;
		else
			appendStringInfoString(buf, ", ");

		appendStringInfoChar(buf, '(');
		foreach(lc, sublist)
		{
			Node	   *col = (Node *) lfirst(lc);

			if (first_col)
				first_col = false;
			else
				appendStringInfoChar(buf, ',');

			/*
			 * Print the value.  Whole-row Vars need special treatment.
			 */
			get_rule_expr_toplevel(col, context, false);
		}
		appendStringInfoChar(buf, ')');
	}
}

/* ----------
 * get_with_clause			- Parse back a WITH clause
 * ----------
 */
static void
get_with_clause(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	const char *sep;
	ListCell   *l;

	if (query->cteList == NIL)
		return;

	if (PRETTY_INDENT(context))
	{
		context->indentLevel += PRETTYINDENT_STD;
		appendStringInfoChar(buf, ' ');
	}

	if (query->hasRecursive)
		sep = "WITH RECURSIVE ";
	else
		sep = "WITH ";
	foreach(l, query->cteList)
	{
		CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);

		appendStringInfoString(buf, sep);
		appendStringInfoString(buf, quote_identifier(cte->ctename));
		if (cte->aliascolnames)
		{
			bool		first = true;
			ListCell   *col;

			appendStringInfoChar(buf, '(');
			foreach(col, cte->aliascolnames)
			{
				if (first)
					first = false;
				else
					appendStringInfoString(buf, ", ");
				appendStringInfoString(buf,
									   quote_identifier(strVal(lfirst(col))));
			}
			appendStringInfoChar(buf, ')');
		}
		appendStringInfoString(buf, " AS ");
		switch (cte->ctematerialized)
		{
			case CTEMaterializeDefault:
				break;
			case CTEMaterializeAlways:
				appendStringInfoString(buf, "MATERIALIZED ");
				break;
			case CTEMaterializeNever:
				appendStringInfoString(buf, "NOT MATERIALIZED ");
				break;
		}
		appendStringInfoChar(buf, '(');
		if (PRETTY_INDENT(context))
			appendContextKeyword(context, "", 0, 0, 0);
		get_query_def((Query *) cte->ctequery, buf, context->namespaces, NULL,
		              true,
					  context->prettyFlags, context->wrapColumn,
					  context->indentLevel);
		if (PRETTY_INDENT(context))
			appendContextKeyword(context, "", 0, 0, 0);
		appendStringInfoChar(buf, ')');

		if (cte->search_clause)
		{
			bool		first = true;
			ListCell   *lc;

			appendStringInfo(buf, " SEARCH %s FIRST BY ",
							 cte->search_clause->search_breadth_first ? "BREADTH" : "DEPTH");

			foreach(lc, cte->search_clause->search_col_list)
			{
				if (first)
					first = false;
				else
					appendStringInfoString(buf, ", ");
				appendStringInfoString(buf,
									   quote_identifier(strVal(lfirst(lc))));
			}

			appendStringInfo(buf, " SET %s", quote_identifier(cte->search_clause->search_seq_column));
		}

		if (cte->cycle_clause)
		{
			bool		first = true;
			ListCell   *lc;

			appendStringInfoString(buf, " CYCLE ");

			foreach(lc, cte->cycle_clause->cycle_col_list)
			{
				if (first)
					first = false;
				else
					appendStringInfoString(buf, ", ");
				appendStringInfoString(buf,
									   quote_identifier(strVal(lfirst(lc))));
			}

			appendStringInfo(buf, " SET %s", quote_identifier(cte->cycle_clause->cycle_mark_column));

			{
				Const	   *cmv = castNode(Const, cte->cycle_clause->cycle_mark_value);
				Const	   *cmd = castNode(Const, cte->cycle_clause->cycle_mark_default);

				if (!(cmv->consttype == BOOLOID && !cmv->constisnull && DatumGetBool(cmv->constvalue) == true &&
					  cmd->consttype == BOOLOID && !cmd->constisnull && DatumGetBool(cmd->constvalue) == false))
				{
					appendStringInfoString(buf, " TO ");
					get_rule_expr(cte->cycle_clause->cycle_mark_value, context, false);
					appendStringInfoString(buf, " DEFAULT ");
					get_rule_expr(cte->cycle_clause->cycle_mark_default, context, false);
				}
			}

			appendStringInfo(buf, " USING %s", quote_identifier(cte->cycle_clause->cycle_path_column));
		}

		sep = ", ";
	}

	if (PRETTY_INDENT(context))
	{
		context->indentLevel -= PRETTYINDENT_STD;
		appendContextKeyword(context, "", 0, 0, 0);
	}
	else
		appendStringInfoChar(buf, ' ');
}

/* ----------
 * get_select_query_def			- Parse back a SELECT parsetree
 * ----------
 */
static void
get_select_query_def(Query *query, deparse_context *context,
					 TupleDesc resultDesc, bool colNamesVisible)
{
	StringInfo	buf = context->buf;
	List	   *save_windowclause;
	List	   *save_windowtlist;
	bool		force_colno;
	ListCell   *l;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/* Set up context for possible window functions */
	save_windowclause = context->windowClause;
	context->windowClause = query->windowClause;
	save_windowtlist = context->windowTList;
	context->windowTList = query->targetList;

	/*
	 * If the Query node has a setOperations tree, then it's the top level of
	 * a UNION/INTERSECT/EXCEPT query; only the WITH, ORDER BY and LIMIT
	 * fields are interesting in the top query itself.
	 */
	if (query->setOperations)
	{
		get_setop_query(query->setOperations, query, context, resultDesc,
						colNamesVisible);
		/* ORDER BY clauses must be simple in this case */
		force_colno = true;
	}
	else
	{
		get_basic_select_query(query, context, resultDesc, colNamesVisible);
		force_colno = false;
	}

	/* Add the ORDER BY clause if given */
	if (query->sortClause != NIL)
	{
		appendContextKeyword(context, " ORDER BY ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_orderby(query->sortClause, query->targetList,
						 force_colno, context);
	}

	/*
	 * Add the LIMIT/OFFSET clauses if given. If non-default options, use the
	 * standard spelling of LIMIT.
	 */
	if (query->limitOffset != NULL)
	{
		appendContextKeyword(context, " OFFSET ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
		get_rule_expr(query->limitOffset, context, false);
	}
	if (query->limitCount != NULL)
	{
		if (query->limitOption == LIMIT_OPTION_WITH_TIES)
		{
			// had to add '(' and ')' here because it fails with casting
			appendContextKeyword(context, " FETCH FIRST (",
								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
			get_rule_expr(query->limitCount, context, false);
			appendStringInfoString(buf, ") ROWS WITH TIES");
		}
		else
		{
			appendContextKeyword(context, " LIMIT ",
								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
			if (IsA(query->limitCount, Const) &&
				((Const *) query->limitCount)->constisnull)
				appendStringInfoString(buf, "ALL");
			else
				get_rule_expr(query->limitCount, context, false);
		}
	}

	/* Add FOR [KEY] UPDATE/SHARE clauses if present */
	if (query->hasForUpdate)
	{
		foreach(l, query->rowMarks)
		{
			RowMarkClause *rc = (RowMarkClause *) lfirst(l);

			/* don't print implicit clauses */
			if (rc->pushedDown)
				continue;

			switch (rc->strength)
			{
				case LCS_NONE:
					/* we intentionally throw an error for LCS_NONE */
					elog(ERROR, "unrecognized LockClauseStrength %d",
						 (int) rc->strength);
					break;
				case LCS_FORKEYSHARE:
					appendContextKeyword(context, " FOR KEY SHARE",
										 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
					break;
				case LCS_FORSHARE:
					appendContextKeyword(context, " FOR SHARE",
										 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
					break;
				case LCS_FORNOKEYUPDATE:
					appendContextKeyword(context, " FOR NO KEY UPDATE",
										 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
					break;
				case LCS_FORUPDATE:
					appendContextKeyword(context, " FOR UPDATE",
										 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
					break;
			}

			appendStringInfo(buf, " OF %s",
							 quote_identifier(get_rtable_name(rc->rti,
															  context)));
			if (rc->waitPolicy == LockWaitError)
				appendStringInfoString(buf, " NOWAIT");
			else if (rc->waitPolicy == LockWaitSkip)
				appendStringInfoString(buf, " SKIP LOCKED");
		}
	}

	context->windowClause = save_windowclause;
	context->windowTList = save_windowtlist;
}

/*
 * Detect whether query looks like SELECT ... FROM VALUES();
 * if so, return the VALUES RTE.  Otherwise return NULL.
 */
static RangeTblEntry *
get_simple_values_rte(Query *query, TupleDesc resultDesc)
{
	RangeTblEntry *result = NULL;
	ListCell   *lc;
	int colno;

	/*
	 * We want to return true even if the Query also contains OLD or NEW rule
	 * RTEs.  So the idea is to scan the rtable and see if there is only one
	 * inFromCl RTE that is a VALUES RTE.
	 */
	foreach(lc, query->rtable)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);

		if (rte->rtekind == RTE_VALUES && rte->inFromCl)
		{
			if (result)
				return NULL;	/* multiple VALUES (probably not possible) */
			result = rte;
		}
		else if (rte->rtekind == RTE_RELATION && !rte->inFromCl)
			continue;			/* ignore rule entries */
		else
			return NULL;		/* something else -> not simple VALUES */
	}

	/*
	 * We don't need to check the targetlist in any great detail, because
	 * parser/analyze.c will never generate a "bare" VALUES RTE --- they only
	 * appear inside auto-generated sub-queries with very restricted
	 * structure.  However, DefineView might have modified the tlist by
	 * injecting new column aliases; so compare tlist resnames against the
	 * RTE's names to detect that.
	 */
	if (result)
	{
		ListCell   *lcn;

		if (list_length(query->targetList) != list_length(result->eref->colnames))
			return NULL;		/* this probably cannot happen */
		colno = 0;
		forboth(lc, query->targetList, lcn, result->eref->colnames)
		{
			TargetEntry *tle = (TargetEntry *) lfirst(lc);
			char	   *cname = strVal(lfirst(lcn));
			char	   *colname;

			if (tle->resjunk)
				return NULL;	/* this probably cannot happen */
			/* compute name that get_target_list would use for column */
			colno++;
			if (resultDesc && colno <= resultDesc->natts)
				colname = NameStr(TupleDescAttr(resultDesc, colno - 1)->attname);
			else
				colname = tle->resname;

			/* does it match the VALUES RTE? */
			if (colname == NULL || strcmp(colname, cname) != 0)
				return NULL;	/* column name has been changed */
		}
	}

	return result;
}

static void
get_basic_select_query(Query *query, deparse_context *context,
					   TupleDesc resultDesc, bool colNamesVisible)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *values_rte;
	char	   *sep;
	ListCell   *l;

	if (PRETTY_INDENT(context))
	{
		context->indentLevel += PRETTYINDENT_STD;
		appendStringInfoChar(buf, ' ');
	}

	/*
	 * If the query looks like SELECT * FROM (VALUES ...), then print just the
	 * VALUES part.  This reverses what transformValuesClause() did at parse
	 * time.
	 */
	values_rte = get_simple_values_rte(query, resultDesc);
	if (values_rte)
	{
		get_values_def(values_rte->values_lists, context);
		return;
	}

	/*
	 * Build up the query string - first we say SELECT
	 */
	if (query->isReturn)
		appendStringInfoString(buf, "RETURN");
	else
		appendStringInfoString(buf, "SELECT");

	/* Add the DISTINCT clause if given */
	if (query->distinctClause != NIL)
	{
		if (query->hasDistinctOn)
		{
			appendStringInfoString(buf, " DISTINCT ON (");
			sep = "";
			foreach(l, query->distinctClause)
			{
				SortGroupClause *srt = (SortGroupClause *) lfirst(l);

				appendStringInfoString(buf, sep);
				get_rule_sortgroupclause(srt->tleSortGroupRef, query->targetList,
										 false, context);
				sep = ", ";
			}
			appendStringInfoChar(buf, ')');
		}
		else
			appendStringInfoString(buf, " DISTINCT");
	}

	/* Then we tell what to select (the targetlist) */
	get_target_list(query->targetList, context, resultDesc, colNamesVisible);

	/* Add the FROM clause if needed */
	get_from_clause(query, " FROM ", context);

	/* Add the WHERE clause if given */
	if (query->jointree->quals != NULL)
	{
		appendContextKeyword(context, " WHERE ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_expr(query->jointree->quals, context, false);
	}

	/* Add the GROUP BY clause if given */
	if (query->groupClause != NULL || query->groupingSets != NULL)
	{
		ParseExprKind save_exprkind;

		appendContextKeyword(context, " GROUP BY ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		if (query->groupDistinct)
			appendStringInfoString(buf, "DISTINCT ");

		save_exprkind = context->special_exprkind;
		context->special_exprkind = EXPR_KIND_GROUP_BY;

		if (query->groupingSets == NIL)
		{
			sep = "";
			foreach(l, query->groupClause)
			{
				SortGroupClause *grp = (SortGroupClause *) lfirst(l);

				appendStringInfoString(buf, sep);
				get_rule_sortgroupclause(grp->tleSortGroupRef, query->targetList,
										 false, context);
				sep = ", ";
			}
		}
		else
		{
			sep = "";
			foreach(l, query->groupingSets)
			{
				GroupingSet *grp = lfirst(l);

				appendStringInfoString(buf, sep);
				get_rule_groupingset(grp, query->targetList, true, context);
				sep = ", ";
			}
		}

		context->special_exprkind = save_exprkind;
	}

	/* Add the HAVING clause if given */
	if (query->havingQual != NULL)
	{
		appendContextKeyword(context, " HAVING ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
		get_rule_expr(query->havingQual, context, false);
	}

	/* Add the WINDOW clause if needed */
	if (query->windowClause != NIL)
		get_rule_windowclause(query, context);
}

/* ----------
 * get_target_list			- Parse back a SELECT target list
 *
 * This is also used for RETURNING lists in INSERT/UPDATE/DELETE.
 *
 * resultDesc and colNamesVisible are as for get_query_def()
 * ----------
 */
static void
get_target_list(List *targetList, deparse_context *context,
				TupleDesc resultDesc, bool colNamesVisible)
{
	StringInfo	buf = context->buf;
	StringInfoData targetbuf;
	bool		last_was_multiline = false;
	char	   *sep;
	int			colno;
	ListCell   *l;

	/* we use targetbuf to hold each TLE's text temporarily */
	initStringInfo(&targetbuf);

	sep = " ";
	colno = 0;
	foreach(l, targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);
		char	   *colname;
		char	   *attname;

		if (tle->resjunk)
			continue;			/* ignore junk entries */

		appendStringInfoString(buf, sep);
		sep = ", ";
		colno++;

		/*
		 * Put the new field text into targetbuf so we can decide after we've
		 * got it whether or not it needs to go on a new line.
		 */
		resetStringInfo(&targetbuf);
		context->buf = &targetbuf;

		/*
		 * We special-case Var nodes rather than using get_rule_expr. This is
		 * needed because get_rule_expr will display a whole-row Var as
		 * "foo.*", which is the preferred notation in most contexts, but at
		 * the top level of a SELECT list it's not right (the parser will
		 * expand that notation into multiple columns, yielding behavior
		 * different from a whole-row Var).  We need to call get_variable
		 * directly so that we can tell it to do the right thing, and so that
		 * we can get the attribute name which is the default AS label.
		 */
		if (tle->expr && (IsA(tle->expr, Var)))
		{
			attname = get_variable((Var *) tle->expr, 0, true, context);
		}
		else
		{
			get_rule_expr((Node *) tle->expr, context, true);

			/*
			 * When colNamesVisible is true, we should always show the
			 * assigned column name explicitly.  Otherwise, show it only if
			 * it's not FigureColname's fallback.
			 */
			attname = colNamesVisible ? NULL : "?column?";
		}

		/*
		 * Figure out what the result column should be called.  In the context
		 * of a view, use the view's tuple descriptor (so as to pick up the
		 * effects of any column RENAME that's been done on the view).
		 * Otherwise, just use what we can find in the TLE.
		 */
		if (resultDesc && colno <= resultDesc->natts)
			colname = NameStr(TupleDescAttr(resultDesc, colno - 1)->attname);
		else
			colname = tle->resname;

		/* Show AS unless the column's name is correct as-is */
		if (colname)			/* resname could be NULL */
		{
			if (attname == NULL || strcmp(attname, colname) != 0)
				appendStringInfo(&targetbuf, " AS %s", quote_identifier(colname));
		}

		/* Restore context's output buffer */
		context->buf = buf;

		/* Consider line-wrapping if enabled */
		if (PRETTY_INDENT(context) && context->wrapColumn >= 0)
		{
			int			leading_nl_pos;

			/* Does the new field start with a new line? */
			if (targetbuf.len > 0 && targetbuf.data[0] == '\n')
				leading_nl_pos = 0;
			else
				leading_nl_pos = -1;

			/* If so, we shouldn't add anything */
			if (leading_nl_pos >= 0)
			{
				/* instead, remove any trailing spaces currently in buf */
				removeStringInfoSpaces(buf);
			}
			else
			{
				char	   *trailing_nl;

				/* Locate the start of the current line in the output buffer */
				trailing_nl = strrchr(buf->data, '\n');
				if (trailing_nl == NULL)
					trailing_nl = buf->data;
				else
					trailing_nl++;

				/*
				 * Add a newline, plus some indentation, if the new field is
				 * not the first and either the new field would cause an
				 * overflow or the last field used more than one line.
				 */
				if (colno > 1 &&
					((strlen(trailing_nl) + targetbuf.len > context->wrapColumn) ||
					 last_was_multiline))
					appendContextKeyword(context, "", -PRETTYINDENT_STD,
										 PRETTYINDENT_STD, PRETTYINDENT_VAR);
			}

			/* Remember this field's multiline status for next iteration */
			last_was_multiline =
				(strchr(targetbuf.data + leading_nl_pos + 1, '\n') != NULL);
		}

		/* Add the new field */
		appendStringInfoString(buf, targetbuf.data);
	}

	/* clean up */
	pfree(targetbuf.data);
}

static void
get_setop_query(Node *setOp, Query *query, deparse_context *context,
				TupleDesc resultDesc, bool colNamesVisible)
{
	StringInfo	buf = context->buf;
	bool		need_paren;

	/* Guard against excessively long or deeply-nested queries */
	CHECK_FOR_INTERRUPTS();
	check_stack_depth();

	if (IsA(setOp, RangeTblRef))
	{
		RangeTblRef *rtr = (RangeTblRef *) setOp;
		RangeTblEntry *rte = rt_fetch(rtr->rtindex, query->rtable);
		Query	   *subquery = rte->subquery;

		Assert(subquery != NULL);
		Assert(subquery->setOperations == NULL);
		/* Need parens if WITH, ORDER BY, FOR UPDATE, or LIMIT; see gram.y */
		need_paren = (subquery->cteList ||
					  subquery->sortClause ||
					  subquery->rowMarks ||
					  subquery->limitOffset ||
					  subquery->limitCount);
		if (need_paren)
			appendStringInfoChar(buf, '(');
		get_query_def(subquery, buf, context->namespaces, resultDesc,
		              colNamesVisible,
					  context->prettyFlags, context->wrapColumn,
					  context->indentLevel);
		if (need_paren)
			appendStringInfoChar(buf, ')');
	}
	else if (IsA(setOp, SetOperationStmt))
	{
		SetOperationStmt *op = (SetOperationStmt *) setOp;
		int			subindent;

		/*
		 * We force parens when nesting two SetOperationStmts, except when the
		 * lefthand input is another setop of the same kind.  Syntactically,
		 * we could omit parens in rather more cases, but it seems best to use
		 * parens to flag cases where the setop operator changes.  If we use
		 * parens, we also increase the indentation level for the child query.
		 *
		 * There are some cases in which parens are needed around a leaf query
		 * too, but those are more easily handled at the next level down (see
		 * code above).
		 */
		if (IsA(op->larg, SetOperationStmt))
		{
			SetOperationStmt *lop = (SetOperationStmt *) op->larg;

			if (op->op == lop->op && op->all == lop->all)
				need_paren = false;
			else
				need_paren = true;
		}
		else
			need_paren = false;

		if (need_paren)
		{
			appendStringInfoChar(buf, '(');
			subindent = PRETTYINDENT_STD;
			appendContextKeyword(context, "", subindent, 0, 0);
		}
		else
			subindent = 0;

		get_setop_query(op->larg, query, context, resultDesc, colNamesVisible);

		if (need_paren)
			appendContextKeyword(context, ") ", -subindent, 0, 0);
		else if (PRETTY_INDENT(context))
			appendContextKeyword(context, "", -subindent, 0, 0);
		else
			appendStringInfoChar(buf, ' ');

		switch (op->op)
		{
			case SETOP_UNION:
				appendStringInfoString(buf, "UNION ");
				break;
			case SETOP_INTERSECT:
				appendStringInfoString(buf, "INTERSECT ");
				break;
			case SETOP_EXCEPT:
				appendStringInfoString(buf, "EXCEPT ");
				break;
			default:
				elog(ERROR, "unrecognized set op: %d",
					 (int) op->op);
		}
		if (op->all)
			appendStringInfoString(buf, "ALL ");

		/* Always parenthesize if RHS is another setop */
		need_paren = IsA(op->rarg, SetOperationStmt);

		/*
		 * The indentation code here is deliberately a bit different from that
		 * for the lefthand input, because we want the line breaks in
		 * different places.
		 */
		if (need_paren)
		{
			appendStringInfoChar(buf, '(');
			subindent = PRETTYINDENT_STD;
		}
		else
			subindent = 0;
		appendContextKeyword(context, "", subindent, 0, 0);

		get_setop_query(op->rarg, query, context, resultDesc, false);

		if (PRETTY_INDENT(context))
			context->indentLevel -= subindent;
		if (need_paren)
			appendContextKeyword(context, ")", 0, 0, 0);
	}
	else
	{
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(setOp));
	}
}

/*
 * Display a sort/group clause.
 *
 * Also returns the expression tree, so caller need not find it again.
 */
static Node *
get_rule_sortgroupclause(Index ref, List *tlist, bool force_colno,
						 deparse_context *context)
{
	StringInfo	buf = context->buf;
	TargetEntry *tle;
	Node	   *expr;

	tle = get_sortgroupref_tle(ref, tlist);
	expr = (Node *) tle->expr;

	/*
	 * Use column-number form if requested by caller.  Otherwise, if
	 * expression is a constant, force it to be dumped with an explicit cast
	 * as decoration --- this is because a simple integer constant is
	 * ambiguous (and will be misinterpreted by findTargetlistEntry()) if we
	 * dump it without any decoration.  If it's anything more complex than a
	 * simple Var, then force extra parens around it, to ensure it can't be
	 * misinterpreted as a cube() or rollup() construct.
	 */
	if (force_colno)
	{
		Assert(!tle->resjunk);
		appendStringInfo(buf, "%d", tle->resno);
	}
	else if (expr && IsA(expr, Const))
		get_const_expr((Const *) expr, context, 1);
	else if (!expr || IsA(expr, Var))
		get_rule_expr(expr, context, true);
	else
	{
		/*
		 * We must force parens for function-like expressions even if
		 * PRETTY_PAREN is off, since those are the ones in danger of
		 * misparsing. For other expressions we need to force them only if
		 * PRETTY_PAREN is on, since otherwise the expression will output them
		 * itself. (We can't skip the parens.)
		 */
		bool		need_paren = (PRETTY_PAREN(context)
								  || IsA(expr, FuncExpr)
								  || IsA(expr, Aggref)
								  || IsA(expr, WindowFunc));

		if (need_paren)
			appendStringInfoChar(context->buf, '(');
		get_rule_expr(expr, context, true);
		if (need_paren)
			appendStringInfoChar(context->buf, ')');
	}

	return expr;
}

/*
 * Display a GroupingSet
 */
static void
get_rule_groupingset(GroupingSet *gset, List *targetlist,
					 bool omit_parens, deparse_context *context)
{
	ListCell   *l;
	StringInfo	buf = context->buf;
	bool		omit_child_parens = true;
	char	   *sep = "";

	switch (gset->kind)
	{
		case GROUPING_SET_EMPTY:
			appendStringInfoString(buf, "()");
			return;

		case GROUPING_SET_SIMPLE:
			{
				if (!omit_parens || list_length(gset->content) != 1)
					appendStringInfoChar(buf, '(');

				foreach(l, gset->content)
				{
					Index		ref = lfirst_int(l);

					appendStringInfoString(buf, sep);
					get_rule_sortgroupclause(ref, targetlist,
											 false, context);
					sep = ", ";
				}

				if (!omit_parens || list_length(gset->content) != 1)
					appendStringInfoChar(buf, ')');
			}
			return;

		case GROUPING_SET_ROLLUP:
			appendStringInfoString(buf, "ROLLUP(");
			break;
		case GROUPING_SET_CUBE:
			appendStringInfoString(buf, "CUBE(");
			break;
		case GROUPING_SET_SETS:
			appendStringInfoString(buf, "GROUPING SETS (");
			omit_child_parens = false;
			break;
	}

	foreach(l, gset->content)
	{
		appendStringInfoString(buf, sep);
		get_rule_groupingset(lfirst(l), targetlist, omit_child_parens, context);
		sep = ", ";
	}

	appendStringInfoChar(buf, ')');
}

/*
 * Display an ORDER BY list.
 */
static void
get_rule_orderby(List *orderList, List *targetList,
				 bool force_colno, deparse_context *context)
{
	StringInfo	buf = context->buf;
	const char *sep;
	ListCell   *l;

	sep = "";
	foreach(l, orderList)
	{
		SortGroupClause *srt = (SortGroupClause *) lfirst(l);
		Node	   *sortexpr;
		Oid			sortcoltype;
		TypeCacheEntry *typentry;

		appendStringInfoString(buf, sep);
		sortexpr = get_rule_sortgroupclause(srt->tleSortGroupRef, targetList,
											force_colno, context);
		sortcoltype = exprType(sortexpr);
		/* See whether operator is default < or > for datatype */
		typentry = lookup_type_cache(sortcoltype,
									 TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
		if (srt->sortop == typentry->lt_opr)
		{
			/* ASC is default, so emit nothing for it */
			if (srt->nulls_first)
				appendStringInfoString(buf, " NULLS FIRST");
		}
		else if (srt->sortop == typentry->gt_opr)
		{
			appendStringInfoString(buf, " DESC");
			/* DESC defaults to NULLS FIRST */
			if (!srt->nulls_first)
				appendStringInfoString(buf, " NULLS LAST");
		}
		else
		{
			appendStringInfo(buf, " USING %s",
							 generate_operator_name(srt->sortop,
													sortcoltype,
													sortcoltype));
			/* be specific to eliminate ambiguity */
			if (srt->nulls_first)
				appendStringInfoString(buf, " NULLS FIRST");
			else
				appendStringInfoString(buf, " NULLS LAST");
		}
		sep = ", ";
	}
}

/*
 * Display a WINDOW clause.
 *
 * Note that the windowClause list might contain only anonymous window
 * specifications, in which case we should print nothing here.
 */
static void
get_rule_windowclause(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	const char *sep;
	ListCell   *l;

	sep = NULL;
	foreach(l, query->windowClause)
	{
		WindowClause *wc = (WindowClause *) lfirst(l);

		if (wc->name == NULL)
			continue;			/* ignore anonymous windows */

		if (sep == NULL)
			appendContextKeyword(context, " WINDOW ",
								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		else
			appendStringInfoString(buf, sep);

		appendStringInfo(buf, "%s AS ", quote_identifier(wc->name));

		get_rule_windowspec(wc, query->targetList, context);

		sep = ", ";
	}
}

/*
 * Display a window definition
 */
static void
get_rule_windowspec(WindowClause *wc, List *targetList,
					deparse_context *context)
{
	StringInfo	buf = context->buf;
	bool		needspace = false;
	const char *sep;
	ListCell   *l;

	appendStringInfoChar(buf, '(');
	if (wc->refname)
	{
		appendStringInfoString(buf, quote_identifier(wc->refname));
		needspace = true;
	}
	/* partition clauses are always inherited, so only print if no refname */
	if (wc->partitionClause && !wc->refname)
	{
		if (needspace)
			appendStringInfoChar(buf, ' ');
		appendStringInfoString(buf, "PARTITION BY ");
		sep = "";
		foreach(l, wc->partitionClause)
		{
			SortGroupClause *grp = (SortGroupClause *) lfirst(l);

			appendStringInfoString(buf, sep);
			get_rule_sortgroupclause(grp->tleSortGroupRef, targetList,
									 false, context);
			sep = ", ";
		}
		needspace = true;
	}
	/* print ordering clause only if not inherited */
	if (wc->orderClause && !wc->copiedOrder)
	{
		if (needspace)
			appendStringInfoChar(buf, ' ');
		appendStringInfoString(buf, "ORDER BY ");
		get_rule_orderby(wc->orderClause, targetList, false, context);
		needspace = true;
	}
	/* framing clause is never inherited, so print unless it's default */
	if (wc->frameOptions & FRAMEOPTION_NONDEFAULT)
	{
		if (needspace)
			appendStringInfoChar(buf, ' ');
		if (wc->frameOptions & FRAMEOPTION_RANGE)
			appendStringInfoString(buf, "RANGE ");
		else if (wc->frameOptions & FRAMEOPTION_ROWS)
			appendStringInfoString(buf, "ROWS ");
		else if (wc->frameOptions & FRAMEOPTION_GROUPS)
			appendStringInfoString(buf, "GROUPS ");
		else
			Assert(false);
		if (wc->frameOptions & FRAMEOPTION_BETWEEN)
			appendStringInfoString(buf, "BETWEEN ");
		if (wc->frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)
			appendStringInfoString(buf, "UNBOUNDED PRECEDING ");
		else if (wc->frameOptions & FRAMEOPTION_START_CURRENT_ROW)
			appendStringInfoString(buf, "CURRENT ROW ");
		else if (wc->frameOptions & FRAMEOPTION_START_OFFSET)
		{
			get_rule_expr(wc->startOffset, context, false);
			if (wc->frameOptions & FRAMEOPTION_START_OFFSET_PRECEDING)
				appendStringInfoString(buf, " PRECEDING ");
			else if (wc->frameOptions & FRAMEOPTION_START_OFFSET_FOLLOWING)
				appendStringInfoString(buf, " FOLLOWING ");
			else
				Assert(false);
		}
		else
			Assert(false);
		if (wc->frameOptions & FRAMEOPTION_BETWEEN)
		{
			appendStringInfoString(buf, "AND ");
			if (wc->frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING)
				appendStringInfoString(buf, "UNBOUNDED FOLLOWING ");
			else if (wc->frameOptions & FRAMEOPTION_END_CURRENT_ROW)
				appendStringInfoString(buf, "CURRENT ROW ");
			else if (wc->frameOptions & FRAMEOPTION_END_OFFSET)
			{
				get_rule_expr(wc->endOffset, context, false);
				if (wc->frameOptions & FRAMEOPTION_END_OFFSET_PRECEDING)
					appendStringInfoString(buf, " PRECEDING ");
				else if (wc->frameOptions & FRAMEOPTION_END_OFFSET_FOLLOWING)
					appendStringInfoString(buf, " FOLLOWING ");
				else
					Assert(false);
			}
			else
				Assert(false);
		}
		if (wc->frameOptions & FRAMEOPTION_EXCLUDE_CURRENT_ROW)
			appendStringInfoString(buf, "EXCLUDE CURRENT ROW ");
		else if (wc->frameOptions & FRAMEOPTION_EXCLUDE_GROUP)
			appendStringInfoString(buf, "EXCLUDE GROUP ");
		else if (wc->frameOptions & FRAMEOPTION_EXCLUDE_TIES)
			appendStringInfoString(buf, "EXCLUDE TIES ");
		/* we will now have a trailing space; remove it */
		buf->len--;
	}
	appendStringInfoChar(buf, ')');
}

/* ----------
 * get_insert_query_def			- Parse back an INSERT parsetree
 * ----------
 */
static void
get_insert_query_def(Query *query, deparse_context *context,
                     bool colNamesVisible)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *select_rte = NULL;
	RangeTblEntry *values_rte = NULL;
	RangeTblEntry *rte;
	ListCell   *l;
	List	   *strippedexprs = NIL;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/*
	 * If it's an INSERT ... SELECT or multi-row VALUES, there will be a
	 * single RTE for the SELECT or VALUES.  Plain VALUES has neither.
	 */
	foreach(l, query->rtable)
	{
		rte = (RangeTblEntry *) lfirst(l);

		if (rte->rtekind == RTE_SUBQUERY)
		{
			if (select_rte)
				elog(ERROR, "too many subquery RTEs in INSERT");
			select_rte = rte;
		}

		if (rte->rtekind == RTE_VALUES)
		{
			if (values_rte)
				elog(ERROR, "too many values RTEs in INSERT");
			values_rte = rte;
		}
	}
	if (select_rte && values_rte)
		elog(ERROR, "both subquery and values RTEs in INSERT");

	/*
	 * Start the query with INSERT INTO relname
	 */
	rte = rt_fetch(query->resultRelation, query->rtable);
	Assert(rte->rtekind == RTE_RELATION);

	if (PRETTY_INDENT(context))
	{
		context->indentLevel += PRETTYINDENT_STD;
		appendStringInfoChar(buf, ' ');
	}
	appendStringInfo(buf, "INSERT INTO %s ",
					 generate_relation_or_shard_name(rte->relid,
													 context->distrelid,
													 context->shardid, NIL));
	/* INSERT requires AS keyword for target alias */
	if (rte->alias != NULL)
		appendStringInfo(buf, "AS %s ",
						 quote_identifier(get_rtable_name(query->resultRelation, context)));

	/*
	 * Add the insert-column-names list.  Any indirection decoration needed on
	 * the column names can be inferred from the top targetlist.
	 */
	if (query->targetList)
	{
		strippedexprs = get_insert_column_names_list(query->targetList,
								buf, context, rte);
	}

	if (query->override)
	{
		if (query->override == OVERRIDING_SYSTEM_VALUE)
			appendStringInfoString(buf, "OVERRIDING SYSTEM VALUE ");
		else if (query->override == OVERRIDING_USER_VALUE)
			appendStringInfoString(buf, "OVERRIDING USER VALUE ");
	}

	if (select_rte)
	{
		/* Add the SELECT */
		get_query_def(select_rte->subquery, buf, context->namespaces, NULL,
		              false,
					  context->prettyFlags, context->wrapColumn,
					  context->indentLevel);
	}
	else if (values_rte)
	{
		/* Add the multi-VALUES expression lists */
		get_values_def(values_rte->values_lists, context);
	}
	else if (strippedexprs)
	{
		/* Add the single-VALUES expression list */
		appendContextKeyword(context, "VALUES (",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 2);
		get_rule_list_toplevel(strippedexprs, context, false);
		appendStringInfoChar(buf, ')');
	}
	else
	{
		/* No expressions, so it must be DEFAULT VALUES */
		appendStringInfoString(buf, "DEFAULT VALUES");
	}

	/* Add ON CONFLICT if present */
	if (query->onConflict)
	{
		OnConflictExpr *confl = query->onConflict;

		appendStringInfoString(buf, " ON CONFLICT");

		if (confl->arbiterElems)
		{
			/* Add the single-VALUES expression list */
			appendStringInfoChar(buf, '(');
			get_rule_expr((Node *) confl->arbiterElems, context, false);
			appendStringInfoChar(buf, ')');

			/* Add a WHERE clause (for partial indexes) if given */
			if (confl->arbiterWhere != NULL)
			{
				bool		save_varprefix;

				/*
				 * Force non-prefixing of Vars, since parser assumes that they
				 * belong to target relation.  WHERE clause does not use
				 * InferenceElem, so this is separately required.
				 */
				save_varprefix = context->varprefix;
				context->varprefix = false;

				appendContextKeyword(context, " WHERE ",
									 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
				get_rule_expr(confl->arbiterWhere, context, false);

				context->varprefix = save_varprefix;
			}
		}
		else if (OidIsValid(confl->constraint))
		{
			char	   *constraint = get_constraint_name(confl->constraint);
			int64 shardId = context->shardid;

			if (shardId > 0)
			{
				AppendShardIdToName(&constraint, shardId);
			}

			if (!constraint)
				elog(ERROR, "cache lookup failed for constraint %u",
					 confl->constraint);
			appendStringInfo(buf, " ON CONSTRAINT %s",
							 quote_identifier(constraint));
		}

		if (confl->action == ONCONFLICT_NOTHING)
		{
			appendStringInfoString(buf, " DO NOTHING");
		}
		else
		{
			appendStringInfoString(buf, " DO UPDATE SET ");
			/* Deparse targetlist */
			get_update_query_targetlist_def(query, confl->onConflictSet,
											context, rte);

			/* Add a WHERE clause if given */
			if (confl->onConflictWhere != NULL)
			{
				appendContextKeyword(context, " WHERE ",
									 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
				get_rule_expr(confl->onConflictWhere, context, false);
			}
		}
	}

	/* Add RETURNING if present */
	if (query->returningList)
	{
		appendContextKeyword(context, " RETURNING",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_target_list(query->returningList, context, NULL, colNamesVisible);
	}
}

/* ----------
 * get_update_query_def			- Parse back an UPDATE parsetree
 * ----------
 */
static void
get_update_query_def(Query *query, deparse_context *context,
                     bool colNamesVisible)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *rte;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/*
	 * Start the query with UPDATE relname SET
	 */
	rte = rt_fetch(query->resultRelation, query->rtable);

	if (PRETTY_INDENT(context))
	{
		appendStringInfoChar(buf, ' ');
		context->indentLevel += PRETTYINDENT_STD;
	}

	/* if it's a shard, do differently */
	if (GetRangeTblKind(rte) == CITUS_RTE_SHARD)
	{
		char *fragmentSchemaName = NULL;
		char *fragmentTableName = NULL;

		ExtractRangeTblExtraData(rte, NULL, &fragmentSchemaName, &fragmentTableName, NULL);

		/* use schema and table name from the remote alias */
		appendStringInfo(buf, "UPDATE %s%s",
						 only_marker(rte),
						 generate_fragment_name(fragmentSchemaName, fragmentTableName));

		if(rte->eref != NULL)
			appendStringInfo(buf, " %s",
					quote_identifier(get_rtable_name(query->resultRelation, context)));
	}
	else
	{
		appendStringInfo(buf, "UPDATE %s%s",
						 only_marker(rte),
						 generate_relation_or_shard_name(rte->relid,
														 context->distrelid,
														 context->shardid, NIL));

		if (rte->alias != NULL)
			appendStringInfo(buf, " %s",
							 quote_identifier(get_rtable_name(query->resultRelation, context)));
	}

	appendStringInfoString(buf, " SET ");

	/* Deparse targetlist */
	get_update_query_targetlist_def(query, query->targetList, context, rte);

	/* Add the FROM clause if needed */
	get_from_clause(query, " FROM ", context);

	/* Add a WHERE clause if given */
	if (query->jointree->quals != NULL)
	{
		appendContextKeyword(context, " WHERE ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_expr(query->jointree->quals, context, false);
	}

	/* Add RETURNING if present */
	if (query->returningList)
	{
		appendContextKeyword(context, " RETURNING",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_target_list(query->returningList, context, NULL, colNamesVisible);
	}
}

/* ----------
 * get_update_query_targetlist_def			- Parse back an UPDATE targetlist
 * ----------
 */
static void
get_update_query_targetlist_def(Query *query, List *targetList,
								deparse_context *context, RangeTblEntry *rte)
{
	StringInfo	buf = context->buf;
	ListCell   *l;
	ListCell   *next_ma_cell;
	int			remaining_ma_columns;
	const char *sep;
	SubLink    *cur_ma_sublink;
	List	   *ma_sublinks;

	/*
	 * Prepare to deal with MULTIEXPR assignments: collect the source SubLinks
	 * into a list.  We expect them to appear, in ID order, in resjunk tlist
	 * entries.
	 */
	ma_sublinks = NIL;
	if (query->hasSubLinks)		/* else there can't be any */
	{
		foreach(l, targetList)
		{
			TargetEntry *tle = (TargetEntry *) lfirst(l);

			if (tle->resjunk && IsA(tle->expr, SubLink))
			{
				SubLink    *sl = (SubLink *) tle->expr;

				if (sl->subLinkType == MULTIEXPR_SUBLINK)
				{
					ma_sublinks = lappend(ma_sublinks, sl);
					Assert(sl->subLinkId == list_length(ma_sublinks));
				}
			}
		}
	}
	next_ma_cell = list_head(ma_sublinks);
	cur_ma_sublink = NULL;
	remaining_ma_columns = 0;

	/* Add the comma separated list of 'attname = value' */
	sep = "";
	foreach(l, targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);
		Node	   *expr;

		if (tle->resjunk)
			continue;			/* ignore junk entries */

		/* Emit separator (OK whether we're in multiassignment or not) */
		appendStringInfoString(buf, sep);
		sep = ", ";

		/*
		 * Check to see if we're starting a multiassignment group: if so,
		 * output a left paren.
		 */
		if (next_ma_cell != NULL && cur_ma_sublink == NULL)
		{
			/*
			 * We must dig down into the expr to see if it's a PARAM_MULTIEXPR
			 * Param.  That could be buried under FieldStores and
			 * SubscriptingRefs and CoerceToDomains (cf processIndirection()),
			 * and underneath those there could be an implicit type coercion.
			 * Because we would ignore implicit type coercions anyway, we
			 * don't need to be as careful as processIndirection() is about
			 * descending past implicit CoerceToDomains.
			 */
			expr = (Node *) tle->expr;
			while (expr)
			{
				if (IsA(expr, FieldStore))
				{
					FieldStore *fstore = (FieldStore *) expr;

					expr = (Node *) linitial(fstore->newvals);
				}
				else if (IsA(expr, SubscriptingRef))
				{
					SubscriptingRef *sbsref = (SubscriptingRef *) expr;

					if (sbsref->refassgnexpr == NULL)
						break;
					expr = (Node *) sbsref->refassgnexpr;
				}
				else if (IsA(expr, CoerceToDomain))
				{
					CoerceToDomain *cdomain = (CoerceToDomain *) expr;

					if (cdomain->coercionformat != COERCE_IMPLICIT_CAST)
						break;
					expr = (Node *) cdomain->arg;
				}
				else
					break;
			}
			expr = strip_implicit_coercions(expr);

			if (expr && IsA(expr, Param) &&
				((Param *) expr)->paramkind == PARAM_MULTIEXPR)
			{
				cur_ma_sublink = (SubLink *) lfirst(next_ma_cell);
				next_ma_cell = lnext(ma_sublinks, next_ma_cell);
				remaining_ma_columns = count_nonjunk_tlist_entries(
																   ((Query *) cur_ma_sublink->subselect)->targetList);
				Assert(((Param *) expr)->paramid ==
					   ((cur_ma_sublink->subLinkId << 16) | 1));
				appendStringInfoChar(buf, '(');
			}
		}

		/*
		 * Put out name of target column; look in the catalogs, not at
		 * tle->resname, since resname will fail to track RENAME.
		 */
		appendStringInfoString(buf,
							   quote_identifier(get_attname(rte->relid,
															tle->resno,
															false)));

		/*
		 * Print any indirection needed (subfields or subscripts), and strip
		 * off the top-level nodes representing the indirection assignments.
		 */
		expr = processIndirection((Node *) tle->expr, context);

		/*
		 * If we're in a multiassignment, skip printing anything more, unless
		 * this is the last column; in which case, what we print should be the
		 * sublink, not the Param.
		 */
		if (cur_ma_sublink != NULL)
		{
			if (--remaining_ma_columns > 0)
				continue;		/* not the last column of multiassignment */
			appendStringInfoChar(buf, ')');
			expr = (Node *) cur_ma_sublink;
			cur_ma_sublink = NULL;
		}

		appendStringInfoString(buf, " = ");

		get_rule_expr(expr, context, false);
	}
}

/* ----------
 * get_delete_query_def			- Parse back a DELETE parsetree
 * ----------
 */
static void
get_delete_query_def(Query *query, deparse_context *context,
                     bool colNamesVisible)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *rte;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/*
	 * Start the query with DELETE FROM relname
	 */
	rte = rt_fetch(query->resultRelation, query->rtable);

	if (PRETTY_INDENT(context))
	{
		appendStringInfoChar(buf, ' ');
		context->indentLevel += PRETTYINDENT_STD;
	}

	/* if it's a shard, do differently */
	if (GetRangeTblKind(rte) == CITUS_RTE_SHARD)
	{
		char *fragmentSchemaName = NULL;
		char *fragmentTableName = NULL;

		ExtractRangeTblExtraData(rte, NULL, &fragmentSchemaName, &fragmentTableName, NULL);

		/* use schema and table name from the remote alias */
		appendStringInfo(buf, "DELETE FROM %s%s",
						 only_marker(rte),
						 generate_fragment_name(fragmentSchemaName, fragmentTableName));

		if(rte->eref != NULL)
			appendStringInfo(buf, " %s",
					quote_identifier(get_rtable_name(query->resultRelation, context)));
	}
	else
	{
		appendStringInfo(buf, "DELETE FROM %s%s",
						 only_marker(rte),
						 generate_relation_or_shard_name(rte->relid,
														 context->distrelid,
														 context->shardid, NIL));

		if (rte->alias != NULL)
			appendStringInfo(buf, " %s",
							 quote_identifier(get_rtable_name(query->resultRelation, context)));
	}

	/* Add the USING clause if given */
	get_from_clause(query, " USING ", context);

	/* Add a WHERE clause if given */
	if (query->jointree->quals != NULL)
	{
		appendContextKeyword(context, " WHERE ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_expr(query->jointree->quals, context, false);
	}

	/* Add RETURNING if present */
	if (query->returningList)
	{
		appendContextKeyword(context, " RETURNING",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_target_list(query->returningList, context, NULL, colNamesVisible);
	}
}

/* ----------
 * get_merge_query_def			- Parse back a MERGE parsetree
 * ----------
 */
static void
get_merge_query_def(Query *query, deparse_context *context)
{
	StringInfo buf = context->buf;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/*
	 * Start the query with MERGE INTO <target>
	 */
	RangeTblEntry *targetRte = ExtractResultRelationRTE(query);

	if (PRETTY_INDENT(context))
	{
		appendStringInfoChar(buf, ' ');
		context->indentLevel += PRETTYINDENT_STD;
	}

	/* if it's a shard, do differently */
	if (GetRangeTblKind(targetRte) == CITUS_RTE_SHARD)
	{
		char *fragmentSchemaName = NULL;
		char *fragmentTableName = NULL;

		ExtractRangeTblExtraData(targetRte, NULL, &fragmentSchemaName, &fragmentTableName, NULL);

		/* use schema and table name from the remote alias */
		appendStringInfo(buf, "MERGE INTO %s%s",
						 only_marker(targetRte),
						 generate_fragment_name(fragmentSchemaName, fragmentTableName));

		if(targetRte->eref != NULL)
			appendStringInfo(buf, " %s",
					quote_identifier(get_rtable_name(query->resultRelation, context)));
	}
	else
	{
		appendStringInfo(buf, "MERGE INTO %s%s",
						 only_marker(targetRte),
						 generate_relation_or_shard_name(targetRte->relid,
										context->distrelid,
										context->shardid, NIL));

		if (targetRte->alias != NULL)
			appendStringInfo(buf, " %s",
							 quote_identifier(get_rtable_name(query->resultRelation, context)));
	}

	/*
	 * Add the MERGE source relation -- USING <source>
	 */
	get_from_clause(query, " USING ", context);

	/*
	 * Add the MERGE ON condition
	 */
	Assert(query->jointree->quals != NULL);
	{
		appendContextKeyword(context, " ON ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_expr(query->jointree->quals, context, false);
	}

	ListCell *actionCell = NULL;
	foreach(actionCell, query->mergeActionList)
	{
		MergeAction *action = (MergeAction *) lfirst(actionCell);

		/* Add WHEN [NOT] MATCHED */
		appendContextKeyword(context, " WHEN",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		appendStringInfo(buf, " %s", action->matched ? "MATCHED" : "NOT MATCHED");

		/* Add optional AND <condition> */
		if (action->qual)
		{
			appendContextKeyword(context, " AND ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
			get_rule_expr(action->qual, context, false);
		}

		appendContextKeyword(context, " THEN",
						 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);

		switch (action->commandType)
		{
			case CMD_INSERT:
			{
				appendStringInfo(buf, " INSERT " );
				List *strippedexprs = NIL;

				if (action->targetList)
				{
					strippedexprs = get_insert_column_names_list(action->targetList,
										buf, context, targetRte);
				}

				if (strippedexprs)
				{
					/* Add the single-VALUES expression list */
					appendContextKeyword(context, "VALUES (",
										 -PRETTYINDENT_STD, PRETTYINDENT_STD, 2);
					get_rule_list_toplevel(strippedexprs, context, false);
					appendStringInfoChar(buf, ')');
				}
				else
				{
					/* No expressions, so it must be DEFAULT VALUES */
					appendStringInfoString(buf, "DEFAULT VALUES");
				}
			}
			break;

			case CMD_UPDATE:
				appendStringInfo(buf, " UPDATE SET " );
				get_update_query_targetlist_def(query, action->targetList,
									context, targetRte);
				break;

			case CMD_DELETE:
				appendStringInfo(buf, " DELETE" );
				break;

			case CMD_NOTHING:
				appendStringInfo(buf, " DO NOTHING " );
				break;

			default:
				elog(ERROR, "unknown action in MERGE WHEN clause");
		}
	}

	/*
	 * RETURNING is not supported in MERGE, so it must be NULL, but if PG adds it later,
	 * we might miss it, let's raise an exception to investigate.
	 */
	if (unlikely(query->returningList))
	{
		elog(ERROR, "Unexpected RETURNING clause in MERGE");
	}

	ereport(DEBUG1, (errmsg("<Deparsed MERGE query: %s>", buf->data)));
}


/* ----------
 * get_utility_query_def			- Parse back a UTILITY parsetree
 * ----------
 */
static void
get_utility_query_def(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;

	if (query->utilityStmt && IsA(query->utilityStmt, NotifyStmt))
	{
		NotifyStmt *stmt = (NotifyStmt *) query->utilityStmt;

		appendContextKeyword(context, "",
							 0, PRETTYINDENT_STD, 1);
		appendStringInfo(buf, "NOTIFY %s",
						 quote_identifier(stmt->conditionname));
		if (stmt->payload)
		{
			appendStringInfoString(buf, ", ");
			simple_quote_literal(buf, stmt->payload);
		}
	}
	else if (query->utilityStmt && IsA(query->utilityStmt, TruncateStmt))
	{
		TruncateStmt *stmt = (TruncateStmt *) query->utilityStmt;
		List *relationList = stmt->relations;
		ListCell *relationCell = NULL;

		appendContextKeyword(context, "",
							 0, PRETTYINDENT_STD, 1);

		appendStringInfo(buf, "TRUNCATE TABLE");

		foreach(relationCell, relationList)
		{
			RangeVar *relationVar = (RangeVar *) lfirst(relationCell);
			Oid relationId = RangeVarGetRelid(relationVar, NoLock, false);
			char *relationName = generate_relation_or_shard_name(relationId,
																 context->distrelid,
																 context->shardid, NIL);
			appendStringInfo(buf, " %s", relationName);

			if (lnext(relationList, relationCell) != NULL)
			{
				appendStringInfo(buf, ",");
			}
		}

		if (stmt->restart_seqs)
		{
			appendStringInfo(buf, " RESTART IDENTITY");
		}

		if (stmt->behavior == DROP_CASCADE)
		{
			appendStringInfo(buf, " CASCADE");
		}
	}
	else
	{
		/* Currently only NOTIFY utility commands can appear in rules */
		elog(ERROR, "unexpected utility statement type");
	}
}

/*
 * Display a Var appropriately.
 *
 * In some cases (currently only when recursing into an unnamed join)
 * the Var's varlevelsup has to be interpreted with respect to a context
 * above the current one; levelsup indicates the offset.
 *
 * If istoplevel is true, the Var is at the top level of a SELECT's
 * targetlist, which means we need special treatment of whole-row Vars.
 * Instead of the normal "tab.*", we'll print "tab.*::typename", which is a
 * dirty hack to prevent "tab.*" from being expanded into multiple columns.
 * (The parser will strip the useless coercion, so no inefficiency is added in
 * dump and reload.)  We used to print just "tab" in such cases, but that is
 * ambiguous and will yield the wrong result if "tab" is also a plain column
 * name in the query.
 *
 * Returns the attname of the Var, or NULL if the Var has no attname (because
 * it is a whole-row Var or a subplan output reference).
 */
static char *
get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *rte;
	AttrNumber	attnum;
	int		varno;
	AttrNumber	varattno;
	int			netlevelsup;
	deparse_namespace *dpns;
	deparse_columns *colinfo;
	char	   *refname;
	char	   *attname;

	/* Find appropriate nesting depth */
	netlevelsup = var->varlevelsup + levelsup;
	if (netlevelsup >= list_length(context->namespaces))
		elog(ERROR, "bogus varlevelsup: %d offset %d",
			 var->varlevelsup, levelsup);
	dpns = (deparse_namespace *) list_nth(context->namespaces,
										  netlevelsup);

	varno = var->varno;
	varattno = var->varattno;


	if (var->varnosyn > 0 && var->varnosyn <= list_length(dpns->rtable) && dpns->plan == NULL) {
		rte = rt_fetch(var->varnosyn, dpns->rtable);

		/*
		 * if the rte var->varnosyn points to is not a regular table and it is a join
		 * then the correct relname will be found with var->varnosyn and var->varattnosyn
		 */
		if (rte->rtekind == RTE_JOIN && rte->relid == 0 && var->varnosyn != var->varno) {
			varno = var->varnosyn;
			varattno = var->varattnosyn;
		}
	}

	/*
	 * Try to find the relevant RTE in this rtable.  In a plan tree, it's
	 * likely that varno is OUTER_VAR or INNER_VAR, in which case we must dig
	 * down into the subplans, or INDEX_VAR, which is resolved similarly. Also
	 * find the aliases previously assigned for this RTE.
	 */
	if (varno >= 1 && varno <= list_length(dpns->rtable))
	{

		/*
		 * We might have been asked to map child Vars to some parent relation.
		 */
		if (context->appendparents && dpns->appendrels)
		{

			int		pvarno = varno;
			AttrNumber	pvarattno = varattno;
			AppendRelInfo *appinfo = dpns->appendrels[pvarno];
			bool		found = false;

			/* Only map up to inheritance parents, not UNION ALL appendrels */
			while (appinfo &&
				   rt_fetch(appinfo->parent_relid,
							dpns->rtable)->rtekind == RTE_RELATION)
			{
				found = false;
				if (pvarattno > 0)	/* system columns stay as-is */
				{
					if (pvarattno > appinfo->num_child_cols)
						break;	/* safety check */
					pvarattno = appinfo->parent_colnos[pvarattno - 1];
					if (pvarattno == 0)
						break;	/* Var is local to child */
				}

				pvarno = appinfo->parent_relid;
				found = true;

				/* If the parent is itself a child, continue up. */
				Assert(pvarno > 0 && pvarno <= list_length(dpns->rtable));
				appinfo = dpns->appendrels[pvarno];
			}

			/*
			 * If we found an ancestral rel, and that rel is included in
			 * appendparents, print that column not the original one.
			 */
			if (found && bms_is_member(pvarno, context->appendparents))
			{
				varno = pvarno;
				varattno = pvarattno;
			}
		}

		rte = rt_fetch(varno, dpns->rtable);
		refname = (char *) list_nth(dpns->rtable_names, varno - 1);
		colinfo = deparse_columns_fetch(varno, dpns);
		attnum = varattno;
	}
	else
	{
		resolve_special_varno((Node *) var, context, get_special_variable,
							  NULL);
		return NULL;
	}

	/*
	 * The planner will sometimes emit Vars referencing resjunk elements of a
	 * subquery's target list (this is currently only possible if it chooses
	 * to generate a "physical tlist" for a SubqueryScan or CteScan node).
	 * Although we prefer to print subquery-referencing Vars using the
	 * subquery's alias, that's not possible for resjunk items since they have
	 * no alias.  So in that case, drill down to the subplan and print the
	 * contents of the referenced tlist item.  This works because in a plan
	 * tree, such Vars can only occur in a SubqueryScan or CteScan node, and
	 * we'll have set dpns->inner_plan to reference the child plan node.
	 */
	if ((rte->rtekind == RTE_SUBQUERY || rte->rtekind == RTE_CTE) &&
		attnum > list_length(rte->eref->colnames) &&
		dpns->inner_plan)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;

		tle = get_tle_by_resno(dpns->inner_tlist, attnum);
		if (!tle)
			elog(ERROR, "invalid attnum %d for relation \"%s\"",
				 attnum, rte->eref->aliasname);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->inner_plan, &save_dpns);

		/*
		 * Force parentheses because our caller probably assumed a Var is a
		 * simple expression.
		 */
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, '(');
		get_rule_expr((Node *) tle->expr, context, true);
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, ')');

		pop_child_plan(dpns, &save_dpns);
		return NULL;
	}

	/*
	 * If it's an unnamed join, look at the expansion of the alias variable.
	 * If it's a simple reference to one of the input vars, then recursively
	 * print the name of that var instead.  When it's not a simple reference,
	 * we have to just print the unqualified join column name.  (This can only
	 * happen with "dangerous" merged columns in a JOIN USING; we took pains
	 * previously to make the unqualified column name unique in such cases.)
	 *
	 * This wouldn't work in decompiling plan trees, because we don't store
	 * joinaliasvars lists after planning; but a plan tree should never
	 * contain a join alias variable.
	 */
	if (rte->rtekind == RTE_JOIN && rte->alias == NULL)
	{
		if (rte->joinaliasvars == NIL)
			elog(ERROR, "cannot decompile join alias var in plan tree");
		if (attnum > 0)
		{
			Var		   *aliasvar;

			aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
			/* we intentionally don't strip implicit coercions here */
			if (aliasvar && IsA(aliasvar, Var))
			{
				return get_variable(aliasvar, var->varlevelsup + levelsup,
									istoplevel, context);
			}
		}

		/*
		 * Unnamed join has no refname.  (Note: since it's unnamed, there is
		 * no way the user could have referenced it to create a whole-row Var
		 * for it.  So we don't have to cover that case below.)
		 */
		Assert(refname == NULL);
	}

	if (attnum == InvalidAttrNumber)
		attname = NULL;
	else if (attnum > 0)
	{
		/* Get column name to use from the colinfo struct */
		if (attnum > colinfo->num_cols)
			elog(ERROR, "invalid attnum %d for relation \"%s\"",
				 attnum, rte->eref->aliasname);
		attname = colinfo->colnames[attnum - 1];

		/*
		 * If we find a Var referencing a dropped column, it seems better to
		 * print something (anything) than to fail.  In general this should
		 * not happen, but it used to be possible for some cases involving
		 * functions returning named composite types, and perhaps there are
		 * still bugs out there.
		 */
		if (attname == NULL)
			attname = "?dropped?column?";
	}
	else if (GetRangeTblKind(rte) == CITUS_RTE_SHARD)
	{
		/* System column on a Citus shard */
		attname = get_attname(rte->relid, attnum, false);
	}
	else
	{
		/* System column - name is fixed, get it from the catalog */
		attname = get_rte_attribute_name(rte, attnum);
	}

	if (refname && (context->varprefix || attname == NULL))
	{
		appendStringInfoString(buf, quote_identifier(refname));
		appendStringInfoChar(buf, '.');
	}
	if (attname)
		appendStringInfoString(buf, quote_identifier(attname));
	else
	{
		appendStringInfoChar(buf, '*');

		if (istoplevel)
		{
			if (GetRangeTblKind(rte) == CITUS_RTE_SHARD)
			{
				/* use rel.*::shard_name instead of rel.*::table_name */
				appendStringInfo(buf, "::%s",
								 generate_rte_shard_name(rte));
			}
			else
			{
				appendStringInfo(buf, "::%s",
								 format_type_with_typemod(var->vartype,
														  var->vartypmod));
			}
		}
	}

	return attname;
}

/*
 * Deparse a Var which references OUTER_VAR, INNER_VAR, or INDEX_VAR.  This
 * routine is actually a callback for get_special_varno, which handles finding
 * the correct TargetEntry.  We get the expression contained in that
 * TargetEntry and just need to deparse it, a job we can throw back on
 * get_rule_expr.
 */
static void
get_special_variable(Node *node, deparse_context *context, void *callback_arg)
{
	StringInfo	buf = context->buf;

	/*
	 * For a non-Var referent, force parentheses because our caller probably
	 *  assumed a Var is a simple expression.
	 */
	if (!IsA(node, Var))
		appendStringInfoChar(buf, '(');
	get_rule_expr(node, context, true);
	if (!IsA(node, Var))
		appendStringInfoChar(buf, ')');
}

/*
 * Chase through plan references to special varnos (OUTER_VAR, INNER_VAR,
 * INDEX_VAR) until we find a real Var or some kind of non-Var node; then,
 * invoke the callback provided.
 */
static void
resolve_special_varno(Node *node, deparse_context *context, rsv_callback callback, void *callback_arg)
{
	Var		   *var;
	deparse_namespace *dpns;

	/* This function is recursive, so let's be paranoid. */
	check_stack_depth();

	/* If it's not a Var, invoke the callback. */
	if (!IsA(node, Var))
	{
		(*callback) (node, context, callback_arg);
		return;
	}

	/* Find appropriate nesting depth */
	var = (Var *) node;
	dpns = (deparse_namespace *) list_nth(context->namespaces,
										  var->varlevelsup);

	/*
	 * It's a special RTE, so recurse.
	 */
	if (var->varno == OUTER_VAR && dpns->outer_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;
		Bitmapset  *save_appendparents;

		tle = get_tle_by_resno(dpns->outer_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for OUTER_VAR var: %d", var->varattno);

		/* If we're descending to the first child of an Append or MergeAppend,
		 * update appendparents.  This will affect deparsing of all Vars
		 * appearing within the eventually-resolved subexpression.
		 */
		save_appendparents = context->appendparents;

		if (IsA(dpns->plan, Append))
			context->appendparents = bms_union(context->appendparents,
											   ((Append *) dpns->plan)->apprelids);
		else if (IsA(dpns->plan, MergeAppend))
			context->appendparents = bms_union(context->appendparents,
											   ((MergeAppend *) dpns->plan)->apprelids);

		push_child_plan(dpns, dpns->outer_plan, &save_dpns);
		resolve_special_varno((Node *) tle->expr, context,
							  callback, callback_arg);
		pop_child_plan(dpns, &save_dpns);
		context->appendparents = save_appendparents;
		return;
	}
	else if (var->varno == INNER_VAR && dpns->inner_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;

		tle = get_tle_by_resno(dpns->inner_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INNER_VAR var: %d", var->varattno);

		push_child_plan(dpns, dpns->inner_plan, &save_dpns);
		resolve_special_varno((Node *) tle->expr, context, callback, callback_arg);
		pop_child_plan(dpns, &save_dpns);
		return;
	}
	else if (var->varno == INDEX_VAR && dpns->index_tlist)
	{
		TargetEntry *tle;

		tle = get_tle_by_resno(dpns->index_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INDEX_VAR var: %d", var->varattno);

		resolve_special_varno((Node *) tle->expr, context, callback, callback_arg);
		return;
	}
	else if (var->varno < 1 || var->varno > list_length(dpns->rtable))
		elog(ERROR, "bogus varno: %d", var->varno);

	/* Not special.  Just invoke the callback. */
	(*callback) (node, context, callback_arg);
}

/*
 * Get the name of a field of an expression of composite type.  The
 * expression is usually a Var, but we handle other cases too.
 *
 * levelsup is an extra offset to interpret the Var's varlevelsup correctly.
 *
 * This is fairly straightforward when the expression has a named composite
 * type; we need only look up the type in the catalogs.  However, the type
 * could also be RECORD.  Since no actual table or view column is allowed to
 * have type RECORD, a Var of type RECORD must refer to a JOIN or FUNCTION RTE
 * or to a subquery output.  We drill down to find the ultimate defining
 * expression and attempt to infer the field name from it.  We ereport if we
 * can't determine the name.
 *
 * Similarly, a PARAM of type RECORD has to refer to some expression of
 * a determinable composite type.
 */
static const char *
get_name_for_var_field(Var *var, int fieldno,
					   int levelsup, deparse_context *context)
{
	RangeTblEntry *rte;
	AttrNumber	attnum;
	int			netlevelsup;
	deparse_namespace *dpns;
	int		varno;
	AttrNumber	varattno;
	TupleDesc	tupleDesc;
	Node	   *expr;

	/*
	 * If it's a RowExpr that was expanded from a whole-row Var, use the
	 * column names attached to it.
	 */
	if (IsA(var, RowExpr))
	{
		RowExpr    *r = (RowExpr *) var;

		if (fieldno > 0 && fieldno <= list_length(r->colnames))
			return strVal(list_nth(r->colnames, fieldno - 1));
	}

	/*
	 * If it's a Param of type RECORD, try to find what the Param refers to.
	 */
	if (IsA(var, Param))
	{
		Param	   *param = (Param *) var;
		ListCell   *ancestor_cell;

		expr = find_param_referent(param, context, &dpns, &ancestor_cell);
		if (expr)
		{
			/* Found a match, so recurse to decipher the field name */
			deparse_namespace save_dpns;
			const char *result;

			push_ancestor_plan(dpns, ancestor_cell, &save_dpns);
			result = get_name_for_var_field((Var *) expr, fieldno,
											0, context);
			pop_ancestor_plan(dpns, &save_dpns);
			return result;
		}
	}

	/*
	 * If it's a Var of type RECORD, we have to find what the Var refers to;
	 * if not, we can use get_expr_result_tupdesc().
	 */
	if (!IsA(var, Var) ||
		var->vartype != RECORDOID)
	{
		tupleDesc = get_expr_result_tupdesc((Node *) var, false);
		/* Got the tupdesc, so we can extract the field name */
		Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
		return NameStr(TupleDescAttr(tupleDesc, fieldno - 1)->attname);
	}

	/* Find appropriate nesting depth */
	netlevelsup = var->varlevelsup + levelsup;
	if (netlevelsup >= list_length(context->namespaces))
		elog(ERROR, "bogus varlevelsup: %d offset %d",
			 var->varlevelsup, levelsup);
	dpns = (deparse_namespace *) list_nth(context->namespaces,
										  netlevelsup);

	varno = var->varno;
	varattno = var->varattno;

	if (var->varnosyn > 0 && var->varnosyn <= list_length(dpns->rtable) && dpns->plan == NULL) {
		rte = rt_fetch(var->varnosyn, dpns->rtable);

		/*
		 * if the rte var->varnosyn points to is not a regular table and it is a join
		 * then the correct relname will be found with var->varnosyn and var->varattnosyn
		 */
		if (rte->rtekind == RTE_JOIN && rte->relid == 0 && var->varnosyn != var->varno) {
			varno = var->varnosyn;
			varattno = var->varattnosyn;
		}
	}

	/*
	 * Try to find the relevant RTE in this rtable.  In a plan tree, it's
	 * likely that varno is OUTER_VAR or INNER_VAR, in which case we must dig
	 * down into the subplans, or INDEX_VAR, which is resolved similarly.
	 */
	if (varno >= 1 && varno <= list_length(dpns->rtable))
	{
		rte = rt_fetch(varno, dpns->rtable);
		attnum = varattno;
	}
	else if (varno == OUTER_VAR && dpns->outer_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;
		const char *result;

		tle = get_tle_by_resno(dpns->outer_tlist, varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for OUTER_VAR var: %d", varattno);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->outer_plan, &save_dpns);

		result = get_name_for_var_field((Var *) tle->expr, fieldno,
										levelsup, context);

		pop_child_plan(dpns, &save_dpns);
		return result;
	}
	else if (varno == INNER_VAR && dpns->inner_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;
		const char *result;

		tle = get_tle_by_resno(dpns->inner_tlist, varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INNER_VAR var: %d", varattno);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->inner_plan, &save_dpns);

		result = get_name_for_var_field((Var *) tle->expr, fieldno,
										levelsup, context);

		pop_child_plan(dpns, &save_dpns);
		return result;
	}
	else if (varno == INDEX_VAR && dpns->index_tlist)
	{
		TargetEntry *tle;
		const char *result;

		tle = get_tle_by_resno(dpns->index_tlist, varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INDEX_VAR var: %d", varattno);

		Assert(netlevelsup == 0);

		result = get_name_for_var_field((Var *) tle->expr, fieldno,
										levelsup, context);

		return result;
	}
	else
	{
		elog(ERROR, "bogus varno: %d", varno);
		return NULL;			/* keep compiler quiet */
	}

	if (attnum == InvalidAttrNumber)
	{
		/* Var is whole-row reference to RTE, so select the right field */
		return get_rte_attribute_name(rte, fieldno);
	}

	/*
	 * This part has essentially the same logic as the parser's
	 * expandRecordVariable() function, but we are dealing with a different
	 * representation of the input context, and we only need one field name
	 * not a TupleDesc.  Also, we need special cases for finding subquery and
	 * CTE subplans when deparsing Plan trees.
	 */
	expr = (Node *) var;		/* default if we can't drill down */

	switch (rte->rtekind)
	{
		case RTE_RELATION:
		case RTE_VALUES:
		case RTE_NAMEDTUPLESTORE:
		case RTE_RESULT:

			/*
			 * This case should not occur: a column of a table or values list
			 * shouldn't have type RECORD.  Fall through and fail (most
			 * likely) at the bottom.
			 */
			break;
		case RTE_SUBQUERY:
			/* Subselect-in-FROM: examine sub-select's output expr */
			{
				if (rte->subquery)
				{
					TargetEntry *ste = get_tle_by_resno(rte->subquery->targetList,
														attnum);

					if (ste == NULL || ste->resjunk)
						elog(ERROR, "subquery %s does not have attribute %d",
							 rte->eref->aliasname, attnum);
					expr = (Node *) ste->expr;
					if (IsA(expr, Var))
					{
						/*
						 * Recurse into the sub-select to see what its Var
						 * refers to. We have to build an additional level of
						 * namespace to keep in step with varlevelsup in the
						 * subselect.
						 */
						deparse_namespace mydpns;
						const char *result;

						set_deparse_for_query(&mydpns, rte->subquery,
											  context->namespaces);

						context->namespaces = lcons(&mydpns,
													context->namespaces);

						result = get_name_for_var_field((Var *) expr, fieldno,
														0, context);

						context->namespaces =
							list_delete_first(context->namespaces);

						return result;
					}
					/* else fall through to inspect the expression */
				}
				else
				{
					/*
					 * We're deparsing a Plan tree so we don't have complete
					 * RTE entries (in particular, rte->subquery is NULL). But
					 * the only place we'd see a Var directly referencing a
					 * SUBQUERY RTE is in a SubqueryScan plan node, and we can
					 * look into the child plan's tlist instead.
					 */
					TargetEntry *tle;
					deparse_namespace save_dpns;
					const char *result;

					if (!dpns->inner_plan)
						elog(ERROR, "failed to find plan for subquery %s",
							 rte->eref->aliasname);
					tle = get_tle_by_resno(dpns->inner_tlist, attnum);
					if (!tle)
						elog(ERROR, "bogus varattno for subquery var: %d",
							 attnum);
					Assert(netlevelsup == 0);
					push_child_plan(dpns, dpns->inner_plan, &save_dpns);

					result = get_name_for_var_field((Var *) tle->expr, fieldno,
													levelsup, context);

					pop_child_plan(dpns, &save_dpns);
					return result;
				}
			}
			break;
		case RTE_JOIN:
			/* Join RTE --- recursively inspect the alias variable */
			if (rte->joinaliasvars == NIL)
				elog(ERROR, "cannot decompile join alias var in plan tree");
			Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
			expr = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
			Assert(expr != NULL);
			/* we intentionally don't strip implicit coercions here */
			if (IsA(expr, Var))
				return get_name_for_var_field((Var *) expr, fieldno,
											  var->varlevelsup + levelsup,
											  context);
			/* else fall through to inspect the expression */
			break;
		case RTE_FUNCTION:
		case RTE_TABLEFUNC:

			/*
			 * We couldn't get here unless a function is declared with one of
			 * its result columns as RECORD, which is not allowed.
			 */
			break;
		case RTE_CTE:
			/* CTE reference: examine subquery's output expr */
			{
				CommonTableExpr *cte = NULL;
				Index		ctelevelsup;
				ListCell   *lc;

				/*
				 * Try to find the referenced CTE using the namespace stack.
				 */
				ctelevelsup = rte->ctelevelsup + netlevelsup;
				if (ctelevelsup >= list_length(context->namespaces))
					lc = NULL;
				else
				{
					deparse_namespace *ctedpns;

					ctedpns = (deparse_namespace *)
						list_nth(context->namespaces, ctelevelsup);
					foreach(lc, ctedpns->ctes)
					{
						cte = (CommonTableExpr *) lfirst(lc);
						if (strcmp(cte->ctename, rte->ctename) == 0)
							break;
					}
				}
				if (lc != NULL)
				{
					Query	   *ctequery = (Query *) cte->ctequery;
					TargetEntry *ste = get_tle_by_resno(GetCTETargetList(cte),
														attnum);

					if (ste == NULL || ste->resjunk)
						elog(ERROR, "subquery %s does not have attribute %d",
							 rte->eref->aliasname, attnum);
					expr = (Node *) ste->expr;
					if (IsA(expr, Var))
					{
						/*
						 * Recurse into the CTE to see what its Var refers to.
						 * We have to build an additional level of namespace
						 * to keep in step with varlevelsup in the CTE.
						 * Furthermore it could be an outer CTE, so we may
						 * have to delete some levels of namespace.
						 */
						List	   *save_nslist = context->namespaces;
						List	   *new_nslist;
						deparse_namespace mydpns;
						const char *result;

						set_deparse_for_query(&mydpns, ctequery,
											  context->namespaces);

						new_nslist = list_copy_tail(context->namespaces,
													ctelevelsup);
						context->namespaces = lcons(&mydpns, new_nslist);

						result = get_name_for_var_field((Var *) expr, fieldno,
														0, context);

						context->namespaces = save_nslist;

						return result;
					}
					/* else fall through to inspect the expression */
				}
				else
				{
					/*
					 * We're deparsing a Plan tree so we don't have a CTE
					 * list.  But the only places we'd see a Var directly
                     * referencing a CTE RTE are in CteScan or WorkTableScan
					 * plan nodes.  For those cases, set_deparse_plan arranged
					 * for dpns->inner_plan to be the plan node that emits the
					 * CTE or RecursiveUnion result, and we can look at its
					 * tlist instead.
					 */
					TargetEntry *tle;
					deparse_namespace save_dpns;
					const char *result;

					if (!dpns->inner_plan)
						elog(ERROR, "failed to find plan for CTE %s",
							 rte->eref->aliasname);
					tle = get_tle_by_resno(dpns->inner_tlist, attnum);
					if (!tle)
						elog(ERROR, "bogus varattno for subquery var: %d",
							 attnum);
					Assert(netlevelsup == 0);
					push_child_plan(dpns, dpns->inner_plan, &save_dpns);

					result = get_name_for_var_field((Var *) tle->expr, fieldno,
													levelsup, context);

					pop_child_plan(dpns, &save_dpns);
					return result;
				}
			}
			break;
	}

	/*
	 * We now have an expression we can't expand any more, so see if
	 * get_expr_result_tupdesc() can do anything with it.
	 */
	tupleDesc = get_expr_result_tupdesc(expr, false);
	/* Got the tupdesc, so we can extract the field name */
	Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
	return NameStr(TupleDescAttr(tupleDesc, fieldno - 1)->attname);
}

/*
 * Try to find the referenced expression for a PARAM_EXEC Param that might
 * reference a parameter supplied by an upper NestLoop or SubPlan plan node.
 *
 * If successful, return the expression and set *dpns_p and *ancestor_cell_p
 * appropriately for calling push_ancestor_plan().  If no referent can be
 * found, return NULL.
 */
static Node *
find_param_referent(Param *param, deparse_context *context,
					deparse_namespace **dpns_p, ListCell **ancestor_cell_p)
{
	/* Initialize output parameters to prevent compiler warnings */
	*dpns_p = NULL;
	*ancestor_cell_p = NULL;

	/*
	 * If it's a PARAM_EXEC parameter, look for a matching NestLoopParam or
	 * SubPlan argument.  This will necessarily be in some ancestor of the
	 * current expression's Plan.
	 */
	if (param->paramkind == PARAM_EXEC)
	{
		deparse_namespace *dpns;
		Plan  *child_plan;
		bool		in_same_plan_level;
		ListCell   *lc;

		dpns = (deparse_namespace *) linitial(context->namespaces);
		child_plan = dpns->plan;
		in_same_plan_level = true;

		foreach(lc, dpns->ancestors)
		{
			Node	   *ancestor = (Node *) lfirst(lc);
			ListCell   *lc2;

			/*
			 * NestLoops transmit params to their inner child only; also, once
			 * we've crawled up out of a subplan, this couldn't possibly be
			 * the right match.
			 */
			if (IsA(ancestor, NestLoop) &&
				child_plan == innerPlan(ancestor) &&
				in_same_plan_level)
			{
				NestLoop   *nl = (NestLoop *) ancestor;

				foreach(lc2, nl->nestParams)
				{
					NestLoopParam *nlp = (NestLoopParam *) lfirst(lc2);

					if (nlp->paramno == param->paramid)
					{
						/* Found a match, so return it */
						*dpns_p = dpns;
						*ancestor_cell_p = lc;
						return (Node *) nlp->paramval;
					}
				}
			}

			/*
			 * Check to see if we're crawling up from a subplan.
			 */
			if(IsA(ancestor, SubPlan))
			{
				SubPlan    *subplan = (SubPlan *) ancestor;
				ListCell   *lc3;
				ListCell   *lc4;

				/* Matched subplan, so check its arguments */
				forboth(lc3, subplan->parParam, lc4, subplan->args)
				{
					int			paramid = lfirst_int(lc3);
					Node	   *arg = (Node *) lfirst(lc4);

					if (paramid == param->paramid)
					{
						/*
						 * Found a match, so return it.  But, since Vars in
						 * the arg are to be evaluated in the surrounding
						 * context, we have to point to the next ancestor item
						 * that is *not* a SubPlan.
						 */
						ListCell   *rest;

						for_each_cell(rest, dpns->ancestors,
									  lnext(dpns->ancestors, lc))
						{
							Node	   *ancestor2 = (Node *) lfirst(rest);

							if (!IsA(ancestor2, SubPlan))
							{
								*dpns_p = dpns;
								*ancestor_cell_p = rest;
								return arg;
							}
						}
						elog(ERROR, "SubPlan cannot be outermost ancestor");
					}
				}

				/* We have emerged from a subplan. */
				in_same_plan_level = false;

				/* SubPlan isn't a kind of Plan, so skip the rest */
				continue;
			}

			/*
			 * Check to see if we're emerging from an initplan of the current
			 * ancestor plan.  Initplans never have any parParams, so no need
			 * to search that list, but we need to know if we should reset
			 * in_same_plan_level.
			 */
			foreach(lc2, ((Plan *) ancestor)->initPlan)
			{
				SubPlan    *subplan = lfirst_node(SubPlan, lc2);

				if (child_plan != (Plan *) list_nth(dpns->subplans,
													subplan->plan_id - 1))
					continue;

				/* No parameters to be had here. */
				Assert(subplan->parParam == NIL);

				/* We have emerged from an initplan. */
				in_same_plan_level = false;
				break;
			}

			/* No luck, crawl up to next ancestor */
			child_plan = (Plan *) ancestor;
		}
	}

	/* No referent found */
	return NULL;
}

/*
 * Display a Param appropriately.
 */
static void
get_parameter(Param *param, deparse_context *context)
{
	Node	   *expr;
	deparse_namespace *dpns;
	ListCell   *ancestor_cell;

	/*
	 * If it's a PARAM_EXEC parameter, try to locate the expression from which
	 * the parameter was computed.  Note that failing to find a referent isn't
	 * an error, since the Param might well be a subplan output rather than an
	 * input.
	 */
	expr = find_param_referent(param, context, &dpns, &ancestor_cell);
	if (expr)
	{
		/* Found a match, so print it */
		deparse_namespace save_dpns;
		bool		save_varprefix;
		bool		need_paren;

		/* Switch attention to the ancestor plan node */
		push_ancestor_plan(dpns, ancestor_cell, &save_dpns);

		/*
		 * Force prefixing of Vars, since they won't belong to the relation
		 * being scanned in the original plan node.
		 */
		save_varprefix = context->varprefix;
		context->varprefix = true;

		/*
		 * A Param's expansion is typically a Var, Aggref, GroupingFunc, or
		 * upper-level Param, which wouldn't need extra parentheses.
		 * Otherwise, insert parens to ensure the expression looks atomic.
		 */
		need_paren = !(IsA(expr, Var) ||
					   IsA(expr, Aggref) ||
                       IsA(expr, GroupingFunc) ||
					   IsA(expr, Param));
		if (need_paren)
			appendStringInfoChar(context->buf, '(');

		get_rule_expr(expr, context, false);

		if (need_paren)
			appendStringInfoChar(context->buf, ')');

		context->varprefix = save_varprefix;

		pop_ancestor_plan(dpns, &save_dpns);

		return;
	}

	/*
	 * If it's an external parameter, see if the outermost namespace provides
	 * function argument names.
	 */
	if (param->paramkind == PARAM_EXTERN && context->namespaces != NIL)
	{
		dpns = llast(context->namespaces);
		if (dpns->argnames &&
			param->paramid > 0 &&
			param->paramid <= dpns->numargs)
		{
			char	   *argname = dpns->argnames[param->paramid - 1];

			if (argname)
			{
				bool		should_qualify = false;
				ListCell   *lc;

				/*
				 * Qualify the parameter name if there are any other deparse
				 * namespaces with range tables.  This avoids qualifying in
				 * trivial cases like "RETURN a + b", but makes it safe in all
				 * other cases.
				 */
				foreach(lc, context->namespaces)
				{
					deparse_namespace *dp_ns = lfirst(lc);

					if (list_length(dp_ns->rtable_names) > 0)
					{
						should_qualify = true;
						break;
					}
				}
				if (should_qualify)
				{
					appendStringInfoString(context->buf, quote_identifier(dpns->funcname));
					appendStringInfoChar(context->buf, '.');
				}

				appendStringInfoString(context->buf, quote_identifier(argname));
				return;
			}
		}
	}

	/*
	 * Not PARAM_EXEC, or couldn't find referent: for base types just print $N.
	 * For composite types, add cast to the parameter to ease remote node detect
	 * the type.
	 */
	if (param->paramtype >= FirstNormalObjectId)
	{
		char *typeName = format_type_with_typemod(param->paramtype, param->paramtypmod);

		appendStringInfo(context->buf, "$%d::%s", param->paramid, typeName);
	}
	else
	{
		appendStringInfo(context->buf, "$%d", param->paramid);
	}
}

/*
 * get_simple_binary_op_name
 *
 * helper function for isSimpleNode
 * will return single char binary operator name, or NULL if it's not
 */
static const char *
get_simple_binary_op_name(OpExpr *expr)
{
	List	   *args = expr->args;

	if (list_length(args) == 2)
	{
		/* binary operator */
		Node	   *arg1 = (Node *) linitial(args);
		Node	   *arg2 = (Node *) lsecond(args);
		const char *op;

		op = generate_operator_name(expr->opno, exprType(arg1), exprType(arg2));
		if (strlen(op) == 1)
			return op;
	}
	return NULL;
}

/*
 * isSimpleNode - check if given node is simple (doesn't need parenthesizing)
 *
 *	true   : simple in the context of parent node's type
 *	false  : not simple
 */
static bool
isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
{
	if (!node)
		return false;

	switch (nodeTag(node))
	{
		case T_Var:
		case T_Const:
		case T_Param:
		case T_CoerceToDomainValue:
		case T_SetToDefault:
		case T_CurrentOfExpr:
			/* single words: always simple */
			return true;

		case T_SubscriptingRef:
		case T_ArrayExpr:
		case T_RowExpr:
		case T_CoalesceExpr:
		case T_MinMaxExpr:
		case T_SQLValueFunction:
		case T_XmlExpr:
		case T_NextValueExpr:
		case T_NullIfExpr:
		case T_Aggref:
        case T_GroupingFunc:
		case T_WindowFunc:
		case T_FuncExpr:
			/* function-like: name(..) or name[..] */
			return true;

			/* CASE keywords act as parentheses */
		case T_CaseExpr:
			return true;

		case T_FieldSelect:

			/*
			 * appears simple since . has top precedence, unless parent is
			 * T_FieldSelect itself!
			 */
			return !IsA(parentNode, FieldSelect);

		case T_FieldStore:

			/*
			 * treat like FieldSelect (probably doesn't matter)
			 */
			return !IsA(parentNode, FieldStore);

		case T_CoerceToDomain:
			/* maybe simple, check args */
			return isSimpleNode((Node *) ((CoerceToDomain *) node)->arg,
								node, prettyFlags);
		case T_RelabelType:
			return isSimpleNode((Node *) ((RelabelType *) node)->arg,
								node, prettyFlags);
		case T_CoerceViaIO:
			return isSimpleNode((Node *) ((CoerceViaIO *) node)->arg,
								node, prettyFlags);
		case T_ArrayCoerceExpr:
			return isSimpleNode((Node *) ((ArrayCoerceExpr *) node)->arg,
								node, prettyFlags);
		case T_ConvertRowtypeExpr:
			return isSimpleNode((Node *) ((ConvertRowtypeExpr *) node)->arg,
								node, prettyFlags);

		case T_OpExpr:
			{
				/* depends on parent node type; needs further checking */
				if (prettyFlags & PRETTYFLAG_PAREN && IsA(parentNode, OpExpr))
				{
					const char *op;
					const char *parentOp;
					bool		is_lopriop;
					bool		is_hipriop;
					bool		is_lopriparent;
					bool		is_hipriparent;

					op = get_simple_binary_op_name((OpExpr *) node);
					if (!op)
						return false;

					/* We know only the basic operators + - and * / % */
					is_lopriop = (strchr("+-", *op) != NULL);
					is_hipriop = (strchr("*/%", *op) != NULL);
					if (!(is_lopriop || is_hipriop))
						return false;

					parentOp = get_simple_binary_op_name((OpExpr *) parentNode);
					if (!parentOp)
						return false;

					is_lopriparent = (strchr("+-", *parentOp) != NULL);
					is_hipriparent = (strchr("*/%", *parentOp) != NULL);
					if (!(is_lopriparent || is_hipriparent))
						return false;

					if (is_hipriop && is_lopriparent)
						return true;	/* op binds tighter than parent */

					if (is_lopriop && is_hipriparent)
						return false;

					/*
					 * Operators are same priority --- can skip parens only if
					 * we have (a - b) - c, not a - (b - c).
					 */
					if (node == (Node *) linitial(((OpExpr *) parentNode)->args))
						return true;

					return false;
				}
				/* else do the same stuff as for T_SubLink et al. */
			}
			/* FALLTHROUGH */

		case T_SubLink:
		case T_NullTest:
		case T_BooleanTest:
		case T_DistinctExpr:
			switch (nodeTag(parentNode))
			{
				case T_FuncExpr:
					{
						/* special handling for casts */
						CoercionForm type = ((FuncExpr *) parentNode)->funcformat;

						if (type == COERCE_EXPLICIT_CAST ||
							type == COERCE_IMPLICIT_CAST)
							return false;
						return true;	/* own parentheses */
					}
				case T_BoolExpr:	/* lower precedence */
				case T_SubscriptingRef:	/* other separators */
				case T_ArrayExpr:	/* other separators */
				case T_RowExpr: /* other separators */
				case T_CoalesceExpr:	/* own parentheses */
				case T_MinMaxExpr:	/* own parentheses */
				case T_XmlExpr: /* own parentheses */
				case T_NullIfExpr:	/* other separators */
				case T_Aggref:	/* own parentheses */
                case T_GroupingFunc: /* own parentheses */
				case T_WindowFunc:	/* own parentheses */
				case T_CaseExpr:	/* other separators */
					return true;
				default:
					return false;
			}

		case T_BoolExpr:
			switch (nodeTag(parentNode))
			{
				case T_BoolExpr:
					if (prettyFlags & PRETTYFLAG_PAREN)
					{
						BoolExprType type;
						BoolExprType parentType;

						type = ((BoolExpr *) node)->boolop;
						parentType = ((BoolExpr *) parentNode)->boolop;
						switch (type)
						{
							case NOT_EXPR:
							case AND_EXPR:
								if (parentType == AND_EXPR || parentType == OR_EXPR)
									return true;
								break;
							case OR_EXPR:
								if (parentType == OR_EXPR)
									return true;
								break;
						}
					}
					return false;
				case T_FuncExpr:
					{
						/* special handling for casts */
						CoercionForm type = ((FuncExpr *) parentNode)->funcformat;

						if (type == COERCE_EXPLICIT_CAST ||
							type == COERCE_IMPLICIT_CAST)
							return false;
						return true;	/* own parentheses */
					}
				case T_SubscriptingRef:	/* other separators */
				case T_ArrayExpr:	/* other separators */
				case T_RowExpr: /* other separators */
				case T_CoalesceExpr:	/* own parentheses */
				case T_MinMaxExpr:	/* own parentheses */
				case T_XmlExpr: /* own parentheses */
				case T_NullIfExpr:	/* other separators */
				case T_Aggref:	/* own parentheses */
                case T_GroupingFunc: /* own parentheses */
				case T_WindowFunc:	/* own parentheses */
				case T_CaseExpr:	/* other separators */
					return true;
				default:
					return false;
			}

		default:
			break;
	}
	/* those we don't know: in dubio complexo */
	return false;
}

/*
 * appendContextKeyword - append a keyword to buffer
 *
 * If prettyPrint is enabled, perform a line break, and adjust indentation.
 * Otherwise, just append the keyword.
 */
static void
appendContextKeyword(deparse_context *context, const char *str,
					 int indentBefore, int indentAfter, int indentPlus)
{
	StringInfo	buf = context->buf;

	if (PRETTY_INDENT(context))
	{
		int			indentAmount;

		context->indentLevel += indentBefore;

		/* remove any trailing spaces currently in the buffer ... */
		removeStringInfoSpaces(buf);
		/* ... then add a newline and some spaces */
		appendStringInfoChar(buf, '\n');

		if (context->indentLevel < PRETTYINDENT_LIMIT)
			indentAmount = Max(context->indentLevel, 0) + indentPlus;
		else
		{
			/*
			 * If we're indented more than PRETTYINDENT_LIMIT characters, try
			 * to conserve horizontal space by reducing the per-level
			 * indentation.  For best results the scale factor here should
			 * divide all the indent amounts that get added to indentLevel
			 * (PRETTYINDENT_STD, etc).  It's important that the indentation
			 * not grow unboundedly, else deeply-nested trees use O(N^2)
			 * whitespace; so we also wrap modulo PRETTYINDENT_LIMIT.
			 */
			indentAmount = PRETTYINDENT_LIMIT +
				(context->indentLevel - PRETTYINDENT_LIMIT) /
				(PRETTYINDENT_STD / 2);
			indentAmount %= PRETTYINDENT_LIMIT;
			/* scale/wrap logic affects indentLevel, but not indentPlus */
			indentAmount += indentPlus;
		}
		appendStringInfoSpaces(buf, indentAmount);

		appendStringInfoString(buf, str);

		context->indentLevel += indentAfter;
		if (context->indentLevel < 0)
			context->indentLevel = 0;
	}
	else
		appendStringInfoString(buf, str);
}

/*
 * removeStringInfoSpaces - delete trailing spaces from a buffer.
 *
 * Possibly this should move to stringinfo.c at some point.
 */
static void
removeStringInfoSpaces(StringInfo str)
{
	while (str->len > 0 && str->data[str->len - 1] == ' ')
		str->data[--(str->len)] = '\0';
}

/*
 * get_rule_expr_paren	- deparse expr using get_rule_expr,
 * embracing the string with parentheses if necessary for prettyPrint.
 *
 * Never embrace if prettyFlags=0, because it's done in the calling node.
 *
 * Any node that does *not* embrace its argument node by sql syntax (with
 * parentheses, non-operator keywords like CASE/WHEN/ON, or comma etc) should
 * use get_rule_expr_paren instead of get_rule_expr so parentheses can be
 * added.
 */
static void
get_rule_expr_paren(Node *node, deparse_context *context,
					bool showimplicit, Node *parentNode)
{
	bool		need_paren;

	need_paren = PRETTY_PAREN(context) &&
		!isSimpleNode(node, parentNode, context->prettyFlags);

	if (need_paren)
		appendStringInfoChar(context->buf, '(');

	get_rule_expr(node, context, showimplicit);

	if (need_paren)
		appendStringInfoChar(context->buf, ')');
}

/* ----------
 * get_rule_expr			- Parse back an expression
 *
 * Note: showimplicit determines whether we display any implicit cast that
 * is present at the top of the expression tree.  It is a passed argument,
 * not a field of the context struct, because we change the value as we
 * recurse down into the expression.  In general we suppress implicit casts
 * when the result type is known with certainty (eg, the arguments of an
 * OR must be boolean).  We display implicit casts for arguments of functions
 * and operators, since this is needed to be certain that the same function
 * or operator will be chosen when the expression is re-parsed.
 * ----------
 */
static void
get_rule_expr(Node *node, deparse_context *context,
			  bool showimplicit)
{
	StringInfo	buf = context->buf;

	if (node == NULL)
		return;

	/* Guard against excessively long or deeply-nested queries */
	CHECK_FOR_INTERRUPTS();
	check_stack_depth();

	/*
	 * Each level of get_rule_expr must emit an indivisible term
	 * (parenthesized if necessary) to ensure result is reparsed into the same
	 * expression tree.  The only exception is that when the input is a List,
	 * we emit the component items comma-separated with no surrounding
	 * decoration; this is convenient for most callers.
	 */
	switch (nodeTag(node))
	{
		case T_Var:
			(void) get_variable((Var *) node, 0, false, context);
			break;

		case T_Const:
			get_const_expr((Const *) node, context, 0);
			break;

		case T_Param:
			get_parameter((Param *) node, context);
			break;

		case T_Aggref:
			get_agg_expr((Aggref *) node, context, (Aggref *) node);
			break;

		case T_GroupingFunc:
			{
				GroupingFunc *gexpr = (GroupingFunc *) node;

				appendStringInfoString(buf, "GROUPING(");
				get_rule_expr((Node *) gexpr->args, context, true);
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_WindowFunc:
			get_windowfunc_expr((WindowFunc *) node, context);
			break;

		case T_SubscriptingRef:
			{
				SubscriptingRef *sbsref = (SubscriptingRef *) node;
				bool		need_parens;

				/*
				 * If the argument is a CaseTestExpr, we must be inside a
				 * FieldStore, ie, we are assigning to an element of an array
				 * within a composite column.  Since we already punted on
				 * displaying the FieldStore's target information, just punt
				 * here too, and display only the assignment source
				 * expression.
				 */
				if (IsA(sbsref->refexpr, CaseTestExpr))
				{
					Assert(sbsref->refassgnexpr);
					get_rule_expr((Node *) sbsref->refassgnexpr,
								  context, showimplicit);
					break;
				}

				/*
				 * Parenthesize the argument unless it's a simple Var or a
				 * FieldSelect.  (In particular, if it's another
				 * SubscriptingRef, we *must* parenthesize to avoid
				 * confusion.)
				 */
				need_parens = !IsA(sbsref->refexpr, Var) &&
					!IsA(sbsref->refexpr, FieldSelect);
				if (need_parens)
					appendStringInfoChar(buf, '(');
				get_rule_expr((Node *) sbsref->refexpr, context, showimplicit);
				if (need_parens)
					appendStringInfoChar(buf, ')');

				/*
				 * If there's a refassgnexpr, we want to print the node in the
				 * format "container[subscripts] := refassgnexpr".  This is
				 * not legal SQL, so decompilation of INSERT or UPDATE
				 * statements should always use processIndirection as part of
				 * the statement-level syntax.  We should only see this when
				 * EXPLAIN tries to print the targetlist of a plan resulting
				 * from such a statement.
				 */
				if (sbsref->refassgnexpr)
				{
					Node	   *refassgnexpr;

					/*
					 * Use processIndirection to print this node's subscripts
					 * as well as any additional field selections or
					 * subscripting in immediate descendants.  It returns the
					 * RHS expr that is actually being "assigned".
					 */
					refassgnexpr = processIndirection(node, context);
					appendStringInfoString(buf, " := ");
					get_rule_expr(refassgnexpr, context, showimplicit);
				}
				else
				{
					/* Just an ordinary container fetch, so print subscripts */
					printSubscripts(sbsref, context);
				}
			}
			break;

		case T_FuncExpr:
			get_func_expr((FuncExpr *) node, context, showimplicit);
			break;

		case T_NamedArgExpr:
			{
				NamedArgExpr *na = (NamedArgExpr *) node;

				appendStringInfo(buf, "%s => ", quote_identifier(na->name));
				get_rule_expr((Node *) na->arg, context, showimplicit);
			}
			break;

		case T_OpExpr:
			get_oper_expr((OpExpr *) node, context);
			break;

		case T_DistinctExpr:
			{
				DistinctExpr *expr = (DistinctExpr *) node;
				List	   *args = expr->args;
				Node	   *arg1 = (Node *) linitial(args);
				Node	   *arg2 = (Node *) lsecond(args);

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren(arg1, context, true, node);
				appendStringInfoString(buf, " IS DISTINCT FROM ");
				get_rule_expr_paren(arg2, context, true, node);
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_NullIfExpr:
			{
				NullIfExpr *nullifexpr = (NullIfExpr *) node;

				appendStringInfoString(buf, "NULLIF(");
				get_rule_expr((Node *) nullifexpr->args, context, true);
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_ScalarArrayOpExpr:
			{
				ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) node;
				List	   *args = expr->args;
				Node	   *arg1 = (Node *) linitial(args);
				Node	   *arg2 = (Node *) lsecond(args);

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren(arg1, context, true, node);
				appendStringInfo(buf, " %s %s (",
								 generate_operator_name(expr->opno,
														exprType(arg1),
														get_base_element_type(exprType(arg2))),
								 expr->useOr ? "ANY" : "ALL");
				get_rule_expr_paren(arg2, context, true, node);

				/*
				 * There's inherent ambiguity in "x op ANY/ALL (y)" when y is
				 * a bare sub-SELECT.  Since we're here, the sub-SELECT must
				 * be meant as a scalar sub-SELECT yielding an array value to
				 * be used in ScalarArrayOpExpr; but the grammar will
				 * preferentially interpret such a construct as an ANY/ALL
				 * SubLink.  To prevent misparsing the output that way, insert
				 * a dummy coercion (which will be stripped by parse analysis,
				 * so no inefficiency is added in dump and reload).  This is
				 * indeed most likely what the user wrote to get the construct
				 * accepted in the first place.
				 */
				if (IsA(arg2, SubLink) &&
					((SubLink *) arg2)->subLinkType == EXPR_SUBLINK)
					appendStringInfo(buf, "::%s",
									 format_type_with_typemod(exprType(arg2),
															  exprTypmod(arg2)));
				appendStringInfoChar(buf, ')');
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_BoolExpr:
			{
				BoolExpr   *expr = (BoolExpr *) node;
				Node	   *first_arg = linitial(expr->args);
				ListCell   *arg;

				switch (expr->boolop)
				{
					case AND_EXPR:
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, '(');
						get_rule_expr_paren(first_arg, context,
											false, node);
						for_each_from(arg, expr->args, 1)
						{
							appendStringInfoString(buf, " AND ");
							get_rule_expr_paren((Node *) lfirst(arg), context,
												false, node);
						}
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, ')');
						break;

					case OR_EXPR:
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, '(');
						get_rule_expr_paren(first_arg, context,
											false, node);
						for_each_from(arg, expr->args, 1)
						{
							appendStringInfoString(buf, " OR ");
							get_rule_expr_paren((Node *) lfirst(arg), context,
												false, node);
						}
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, ')');
						break;

					case NOT_EXPR:
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, '(');
						appendStringInfoString(buf, "NOT ");
						get_rule_expr_paren(first_arg, context,
											false, node);
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, ')');
						break;

					default:
						elog(ERROR, "unrecognized boolop: %d",
							 (int) expr->boolop);
				}
			}
			break;

		case T_SubLink:
			get_sublink_expr((SubLink *) node, context);
			break;

		case T_SubPlan:
			{
				SubPlan    *subplan = (SubPlan *) node;

				/*
				 * We cannot see an already-planned subplan in rule deparsing,
				 * only while EXPLAINing a query plan.  We don't try to
				 * reconstruct the original SQL, just reference the subplan
				 * that appears elsewhere in EXPLAIN's result.
				 */
				if (subplan->useHashTable)
					appendStringInfo(buf, "(hashed %s)", subplan->plan_name);
				else
					appendStringInfo(buf, "(%s)", subplan->plan_name);
			}
			break;

		case T_AlternativeSubPlan:
			{
				AlternativeSubPlan *asplan = (AlternativeSubPlan *) node;
				ListCell   *lc;

				/*
				 * This case cannot be reached in normal usage, since no
				 * AlternativeSubPlan can appear either in parsetrees or
				 * finished plan trees.  We keep it just in case somebody
				 * wants to use this code to print planner data structures.
				 */
				appendStringInfoString(buf, "(alternatives: ");
				foreach(lc, asplan->subplans)
				{
					SubPlan    *splan = lfirst_node(SubPlan, lc);

					if (splan->useHashTable)
						appendStringInfo(buf, "hashed %s", splan->plan_name);
					else
						appendStringInfoString(buf, splan->plan_name);
					if (lnext(asplan->subplans, lc))
						appendStringInfoString(buf, " or ");
				}
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_FieldSelect:
			{
				FieldSelect *fselect = (FieldSelect *) node;
				Node	   *arg = (Node *) fselect->arg;
				int			fno = fselect->fieldnum;
				const char *fieldname;
				bool		need_parens;

				/*
				 * Parenthesize the argument unless it's an SubscriptingRef or
				 * another FieldSelect.  Note in particular that it would be
				 * WRONG to not parenthesize a Var argument; simplicity is not
				 * the issue here, having the right number of names is.
				 */
				need_parens = !IsA(arg, SubscriptingRef) &&
					!IsA(arg, FieldSelect);
				if (need_parens)
					appendStringInfoChar(buf, '(');
				get_rule_expr(arg, context, true);
				if (need_parens)
					appendStringInfoChar(buf, ')');

				/*
				 * Get and print the field name.
				 */
				fieldname = get_name_for_var_field((Var *) arg, fno,
												   0, context);
				appendStringInfo(buf, ".%s", quote_identifier(fieldname));
			}
			break;

		case T_FieldStore:
			{
				FieldStore *fstore = (FieldStore *) node;
				bool		need_parens;

				/*
				 * There is no good way to represent a FieldStore as real SQL,
				 * so decompilation of INSERT or UPDATE statements should
				 * always use processIndirection as part of the
				 * statement-level syntax.  We should only get here when
				 * EXPLAIN tries to print the targetlist of a plan resulting
				 * from such a statement.  The plan case is even harder than
				 * ordinary rules would be, because the planner tries to
				 * collapse multiple assignments to the same field or subfield
				 * into one FieldStore; so we can see a list of target fields
				 * not just one, and the arguments could be FieldStores
				 * themselves.  We don't bother to try to print the target
				 * field names; we just print the source arguments, with a
				 * ROW() around them if there's more than one.  This isn't
				 * terribly complete, but it's probably good enough for
				 * EXPLAIN's purposes; especially since anything more would be
				 * either hopelessly confusing or an even poorer
				 * representation of what the plan is actually doing.
				 */
				need_parens = (list_length(fstore->newvals) != 1);
				if (need_parens)
					appendStringInfoString(buf, "ROW(");
				get_rule_expr((Node *) fstore->newvals, context, showimplicit);
				if (need_parens)
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_RelabelType:
			{
				RelabelType *relabel = (RelabelType *) node;
				Node	   *arg = (Node *) relabel->arg;

				if (relabel->relabelformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  relabel->resulttype,
									  relabel->resulttypmod,
									  node);
				}
			}
			break;

		case T_CoerceViaIO:
			{
				CoerceViaIO *iocoerce = (CoerceViaIO *) node;
				Node	   *arg = (Node *) iocoerce->arg;

				if (iocoerce->coerceformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  iocoerce->resulttype,
									  -1,
									  node);
				}
			}
			break;

		case T_ArrayCoerceExpr:
			{
				ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) node;
				Node	   *arg = (Node *) acoerce->arg;

				if (acoerce->coerceformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  acoerce->resulttype,
									  acoerce->resulttypmod,
									  node);
				}
			}
			break;

		case T_ConvertRowtypeExpr:
			{
				ConvertRowtypeExpr *convert = (ConvertRowtypeExpr *) node;
				Node	   *arg = (Node *) convert->arg;

				if (convert->convertformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  convert->resulttype, -1,
									  node);
				}
			}
			break;

		case T_CollateExpr:
			{
				CollateExpr *collate = (CollateExpr *) node;
				Node	   *arg = (Node *) collate->arg;

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren(arg, context, showimplicit, node);
				appendStringInfo(buf, " COLLATE %s",
								 generate_collation_name(collate->collOid));
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_CaseExpr:
			{
				CaseExpr   *caseexpr = (CaseExpr *) node;
				ListCell   *temp;

				appendContextKeyword(context, "CASE",
									 0, PRETTYINDENT_VAR, 0);
				if (caseexpr->arg)
				{
					appendStringInfoChar(buf, ' ');
					get_rule_expr((Node *) caseexpr->arg, context, true);
				}
				foreach(temp, caseexpr->args)
				{
					CaseWhen   *when = (CaseWhen *) lfirst(temp);
					Node	   *w = (Node *) when->expr;

					if (caseexpr->arg)
					{
						/*
						 * The parser should have produced WHEN clauses of the
						 * form "CaseTestExpr = RHS", possibly with an
						 * implicit coercion inserted above the CaseTestExpr.
						 * For accurate decompilation of rules it's essential
						 * that we show just the RHS.  However in an
						 * expression that's been through the optimizer, the
						 * WHEN clause could be almost anything (since the
						 * equality operator could have been expanded into an
						 * inline function).  If we don't recognize the form
						 * of the WHEN clause, just punt and display it as-is.
						 */
						if (IsA(w, OpExpr))
						{
							List	   *args = ((OpExpr *) w)->args;

							if (list_length(args) == 2 &&
								IsA(strip_implicit_coercions(linitial(args)),
									CaseTestExpr))
								w = (Node *) lsecond(args);
						}
					}

					if (!PRETTY_INDENT(context))
						appendStringInfoChar(buf, ' ');
					appendContextKeyword(context, "WHEN ",
										 0, 0, 0);
					get_rule_expr(w, context, false);
					appendStringInfoString(buf, " THEN ");
					get_rule_expr((Node *) when->result, context, true);
				}
				if (!PRETTY_INDENT(context))
					appendStringInfoChar(buf, ' ');
				appendContextKeyword(context, "ELSE ",
									 0, 0, 0);
				get_rule_expr((Node *) caseexpr->defresult, context, true);
				if (!PRETTY_INDENT(context))
					appendStringInfoChar(buf, ' ');
				appendContextKeyword(context, "END",
									 -PRETTYINDENT_VAR, 0, 0);
			}
			break;

		case T_CaseTestExpr:
			{
				/*
				 * Normally we should never get here, since for expressions
				 * that can contain this node type we attempt to avoid
				 * recursing to it.  But in an optimized expression we might
				 * be unable to avoid that (see comments for CaseExpr).  If we
				 * do see one, print it as CASE_TEST_EXPR.
				 */
				appendStringInfoString(buf, "CASE_TEST_EXPR");
			}
			break;

		case T_ArrayExpr:
			{
				ArrayExpr  *arrayexpr = (ArrayExpr *) node;

				appendStringInfoString(buf, "ARRAY[");
				get_rule_expr((Node *) arrayexpr->elements, context, true);
				appendStringInfoChar(buf, ']');

				/*
				 * If the array isn't empty, we assume its elements are
				 * coerced to the desired type.  If it's empty, though, we
				 * need an explicit coercion to the array type.
				 */
				if (arrayexpr->elements == NIL)
					appendStringInfo(buf, "::%s",
									 format_type_with_typemod(arrayexpr->array_typeid, -1));
			}
			break;

		case T_RowExpr:
			{
				RowExpr    *rowexpr = (RowExpr *) node;
				TupleDesc	tupdesc = NULL;
				ListCell   *arg;
				int			i;
				char	   *sep;

				/*
				 * If it's a named type and not RECORD, we may have to skip
				 * dropped columns and/or claim there are NULLs for added
				 * columns.
				 */
				if (rowexpr->row_typeid != RECORDOID)
				{
					tupdesc = lookup_rowtype_tupdesc(rowexpr->row_typeid, -1);
					Assert(list_length(rowexpr->args) <= tupdesc->natts);
				}

				/*
				 * SQL99 allows "ROW" to be omitted when there is more than
				 * one column, but for simplicity we always print it.
				 */
				appendStringInfoString(buf, "ROW(");
				sep = "";
				i = 0;
				foreach(arg, rowexpr->args)
				{
					Node	   *e = (Node *) lfirst(arg);

					if (tupdesc == NULL ||
						!TupleDescAttr(tupdesc, i)->attisdropped)
					{
						appendStringInfoString(buf, sep);
						/* Whole-row Vars need special treatment here */
						get_rule_expr_toplevel(e, context, true);
						sep = ", ";
					}
					i++;
				}
				if (tupdesc != NULL)
				{
					while (i < tupdesc->natts)
					{
						if (!TupleDescAttr(tupdesc, i)->attisdropped)
						{
							appendStringInfoString(buf, sep);
							appendStringInfoString(buf, "NULL");
							sep = ", ";
						}
						i++;
					}

					ReleaseTupleDesc(tupdesc);
				}
				appendStringInfoChar(buf, ')');
				if (rowexpr->row_format == COERCE_EXPLICIT_CAST)
					appendStringInfo(buf, "::%s",
									 format_type_with_typemod(rowexpr->row_typeid, -1));
			}
			break;

		case T_RowCompareExpr:
			{
				RowCompareExpr *rcexpr = (RowCompareExpr *) node;

				/*
				 * SQL99 allows "ROW" to be omitted when there is more than
				 * one column, but for simplicity we always print it.  Within
				 * a ROW expression, whole-row Vars need special treatment, so
				 * use get_rule_list_toplevel.
				 */
				appendStringInfoString(buf, "(ROW(");
				get_rule_list_toplevel(rcexpr->largs, context, true);

				/*
				 * We assume that the name of the first-column operator will
				 * do for all the rest too.  This is definitely open to
				 * failure, eg if some but not all operators were renamed
				 * since the construct was parsed, but there seems no way to
				 * be perfect.
				 */
				appendStringInfo(buf, ") %s ROW(",
								 generate_operator_name(linitial_oid(rcexpr->opnos),
														exprType(linitial(rcexpr->largs)),
														exprType(linitial(rcexpr->rargs))));
				get_rule_list_toplevel(rcexpr->rargs, context, true);
				appendStringInfoString(buf, "))");
			}
			break;

		case T_CoalesceExpr:
			{
				CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;

				appendStringInfoString(buf, "COALESCE(");
				get_rule_expr((Node *) coalesceexpr->args, context, true);
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_MinMaxExpr:
			{
				MinMaxExpr *minmaxexpr = (MinMaxExpr *) node;

				switch (minmaxexpr->op)
				{
					case IS_GREATEST:
						appendStringInfoString(buf, "GREATEST(");
						break;
					case IS_LEAST:
						appendStringInfoString(buf, "LEAST(");
						break;
				}
				get_rule_expr((Node *) minmaxexpr->args, context, true);
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_SQLValueFunction:
			{
				SQLValueFunction *svf = (SQLValueFunction *) node;

				/*
				 * Note: this code knows that typmod for time, timestamp, and
				 * timestamptz just prints as integer.
				 */
				switch (svf->op)
				{
					case SVFOP_CURRENT_DATE:
						appendStringInfoString(buf, "CURRENT_DATE");
						break;
					case SVFOP_CURRENT_TIME:
						appendStringInfoString(buf, "CURRENT_TIME");
						break;
					case SVFOP_CURRENT_TIME_N:
						appendStringInfo(buf, "CURRENT_TIME(%d)", svf->typmod);
						break;
					case SVFOP_CURRENT_TIMESTAMP:
						appendStringInfoString(buf, "CURRENT_TIMESTAMP");
						break;
					case SVFOP_CURRENT_TIMESTAMP_N:
						appendStringInfo(buf, "CURRENT_TIMESTAMP(%d)",
										 svf->typmod);
						break;
					case SVFOP_LOCALTIME:
						appendStringInfoString(buf, "LOCALTIME");
						break;
					case SVFOP_LOCALTIME_N:
						appendStringInfo(buf, "LOCALTIME(%d)", svf->typmod);
						break;
					case SVFOP_LOCALTIMESTAMP:
						appendStringInfoString(buf, "LOCALTIMESTAMP");
						break;
					case SVFOP_LOCALTIMESTAMP_N:
						appendStringInfo(buf, "LOCALTIMESTAMP(%d)",
										 svf->typmod);
						break;
					case SVFOP_CURRENT_ROLE:
						appendStringInfoString(buf, "CURRENT_ROLE");
						break;
					case SVFOP_CURRENT_USER:
						appendStringInfoString(buf, "CURRENT_USER");
						break;
					case SVFOP_USER:
						appendStringInfoString(buf, "USER");
						break;
					case SVFOP_SESSION_USER:
						appendStringInfoString(buf, "SESSION_USER");
						break;
					case SVFOP_CURRENT_CATALOG:
						appendStringInfoString(buf, "CURRENT_CATALOG");
						break;
					case SVFOP_CURRENT_SCHEMA:
						appendStringInfoString(buf, "CURRENT_SCHEMA");
						break;
				}
			}
			break;

		case T_XmlExpr:
			{
				XmlExpr    *xexpr = (XmlExpr *) node;
				bool		needcomma = false;
				ListCell   *arg;
				ListCell   *narg;
				Const	   *con;

				switch (xexpr->op)
				{
					case IS_XMLCONCAT:
						appendStringInfoString(buf, "XMLCONCAT(");
						break;
					case IS_XMLELEMENT:
						appendStringInfoString(buf, "XMLELEMENT(");
						break;
					case IS_XMLFOREST:
						appendStringInfoString(buf, "XMLFOREST(");
						break;
					case IS_XMLPARSE:
						appendStringInfoString(buf, "XMLPARSE(");
						break;
					case IS_XMLPI:
						appendStringInfoString(buf, "XMLPI(");
						break;
					case IS_XMLROOT:
						appendStringInfoString(buf, "XMLROOT(");
						break;
					case IS_XMLSERIALIZE:
						appendStringInfoString(buf, "XMLSERIALIZE(");
						break;
					case IS_DOCUMENT:
						break;
				}
				if (xexpr->op == IS_XMLPARSE || xexpr->op == IS_XMLSERIALIZE)
				{
					if (xexpr->xmloption == XMLOPTION_DOCUMENT)
						appendStringInfoString(buf, "DOCUMENT ");
					else
						appendStringInfoString(buf, "CONTENT ");
				}
				if (xexpr->name)
				{
					appendStringInfo(buf, "NAME %s",
									 quote_identifier(map_xml_name_to_sql_identifier(xexpr->name)));
					needcomma = true;
				}
				if (xexpr->named_args)
				{
					if (xexpr->op != IS_XMLFOREST)
					{
						if (needcomma)
							appendStringInfoString(buf, ", ");
						appendStringInfoString(buf, "XMLATTRIBUTES(");
						needcomma = false;
					}
					forboth(arg, xexpr->named_args, narg, xexpr->arg_names)
					{
						Node	   *e = (Node *) lfirst(arg);
						char	   *argname = strVal(lfirst(narg));

						if (needcomma)
							appendStringInfoString(buf, ", ");
						get_rule_expr((Node *) e, context, true);
						appendStringInfo(buf, " AS %s",
										 quote_identifier(map_xml_name_to_sql_identifier(argname)));
						needcomma = true;
					}
					if (xexpr->op != IS_XMLFOREST)
						appendStringInfoChar(buf, ')');
				}
				if (xexpr->args)
				{
					if (needcomma)
						appendStringInfoString(buf, ", ");
					switch (xexpr->op)
					{
						case IS_XMLCONCAT:
						case IS_XMLELEMENT:
						case IS_XMLFOREST:
						case IS_XMLPI:
						case IS_XMLSERIALIZE:
							/* no extra decoration needed */
							get_rule_expr((Node *) xexpr->args, context, true);
							break;
						case IS_XMLPARSE:
							Assert(list_length(xexpr->args) == 2);

							get_rule_expr((Node *) linitial(xexpr->args),
										  context, true);

							con = lsecond_node(Const, xexpr->args);
							Assert(!con->constisnull);
							if (DatumGetBool(con->constvalue))
								appendStringInfoString(buf,
													   " PRESERVE WHITESPACE");
							else
								appendStringInfoString(buf,
													   " STRIP WHITESPACE");
							break;
						case IS_XMLROOT:
							Assert(list_length(xexpr->args) == 3);

							get_rule_expr((Node *) linitial(xexpr->args),
										  context, true);

							appendStringInfoString(buf, ", VERSION ");
							con = (Const *) lsecond(xexpr->args);
							if (IsA(con, Const) &&
								con->constisnull)
								appendStringInfoString(buf, "NO VALUE");
							else
								get_rule_expr((Node *) con, context, false);

							con = lthird_node(Const, xexpr->args);
							if (con->constisnull)
								 /* suppress STANDALONE NO VALUE */ ;
							else
							{
								switch (DatumGetInt32(con->constvalue))
								{
									case XML_STANDALONE_YES:
										appendStringInfoString(buf,
															   ", STANDALONE YES");
										break;
									case XML_STANDALONE_NO:
										appendStringInfoString(buf,
															   ", STANDALONE NO");
										break;
									case XML_STANDALONE_NO_VALUE:
										appendStringInfoString(buf,
															   ", STANDALONE NO VALUE");
										break;
									default:
										break;
								}
							}
							break;
						case IS_DOCUMENT:
							get_rule_expr_paren((Node *) xexpr->args, context, false, node);
							break;
					}
				}
				if (xexpr->op == IS_XMLSERIALIZE)
					appendStringInfo(buf, " AS %s",
									 format_type_with_typemod(xexpr->type,
															  xexpr->typmod));
				if (xexpr->op == IS_DOCUMENT)
					appendStringInfoString(buf, " IS DOCUMENT");
				else
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_NullTest:
			{
				NullTest   *ntest = (NullTest *) node;

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren((Node *) ntest->arg, context, true, node);

				/*
				 * For scalar inputs, we prefer to print as IS [NOT] NULL,
				 * which is shorter and traditional.  If it's a rowtype input
				 * but we're applying a scalar test, must print IS [NOT]
				 * DISTINCT FROM NULL to be semantically correct.
				 */
				if (ntest->argisrow ||
					!type_is_rowtype(exprType((Node *) ntest->arg)))
				{
					switch (ntest->nulltesttype)
					{
						case IS_NULL:
							appendStringInfoString(buf, " IS NULL");
							break;
						case IS_NOT_NULL:
							appendStringInfoString(buf, " IS NOT NULL");
							break;
						default:
							elog(ERROR, "unrecognized nulltesttype: %d",
								 (int) ntest->nulltesttype);
					}
				}
				else
				{
					switch (ntest->nulltesttype)
					{
						case IS_NULL:
							appendStringInfoString(buf, " IS NOT DISTINCT FROM NULL");
							break;
						case IS_NOT_NULL:
							appendStringInfoString(buf, " IS DISTINCT FROM NULL");
							break;
						default:
							elog(ERROR, "unrecognized nulltesttype: %d",
								 (int) ntest->nulltesttype);
					}
				}
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_BooleanTest:
			{
				BooleanTest *btest = (BooleanTest *) node;

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren((Node *) btest->arg, context, false, node);
				switch (btest->booltesttype)
				{
					case IS_TRUE:
						appendStringInfoString(buf, " IS TRUE");
						break;
					case IS_NOT_TRUE:
						appendStringInfoString(buf, " IS NOT TRUE");
						break;
					case IS_FALSE:
						appendStringInfoString(buf, " IS FALSE");
						break;
					case IS_NOT_FALSE:
						appendStringInfoString(buf, " IS NOT FALSE");
						break;
					case IS_UNKNOWN:
						appendStringInfoString(buf, " IS UNKNOWN");
						break;
					case IS_NOT_UNKNOWN:
						appendStringInfoString(buf, " IS NOT UNKNOWN");
						break;
					default:
						elog(ERROR, "unrecognized booltesttype: %d",
							 (int) btest->booltesttype);
				}
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_CoerceToDomain:
			{
				CoerceToDomain *ctest = (CoerceToDomain *) node;
				Node	   *arg = (Node *) ctest->arg;

				if (ctest->coercionformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr(arg, context, false);
				}
				else
				{
					get_coercion_expr(arg, context,
									  ctest->resulttype,
									  ctest->resulttypmod,
									  node);
				}
			}
			break;

		case T_CoerceToDomainValue:
			appendStringInfoString(buf, "VALUE");
			break;

		case T_SetToDefault:
			appendStringInfoString(buf, "DEFAULT");
			break;

		case T_CurrentOfExpr:
			{
				CurrentOfExpr *cexpr = (CurrentOfExpr *) node;

				if (cexpr->cursor_name)
					appendStringInfo(buf, "CURRENT OF %s",
									 quote_identifier(cexpr->cursor_name));
				else
					appendStringInfo(buf, "CURRENT OF $%d",
									 cexpr->cursor_param);
			}
			break;

		case T_NextValueExpr:
			{
				NextValueExpr *nvexpr = (NextValueExpr *) node;

				/*
				 * This isn't exactly nextval(), but that seems close enough
				 * for EXPLAIN's purposes.
				 */
				appendStringInfoString(buf, "nextval(");
				simple_quote_literal(buf,
									 generate_relation_name(nvexpr->seqid,
															NIL));
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_InferenceElem:
			{
				InferenceElem *iexpr = (InferenceElem *) node;
				bool		save_varprefix;
				bool		need_parens;

				/*
				 * InferenceElem can only refer to target relation, so a
				 * prefix is not useful, and indeed would cause parse errors.
				 */
				save_varprefix = context->varprefix;
				context->varprefix = false;

				/*
				 * Parenthesize the element unless it's a simple Var or a bare
				 * function call.  Follows pg_get_indexdef_worker().
				 */
				need_parens = !IsA(iexpr->expr, Var);
				if (IsA(iexpr->expr, FuncExpr) &&
					((FuncExpr *) iexpr->expr)->funcformat ==
					COERCE_EXPLICIT_CALL)
					need_parens = false;

				if (need_parens)
					appendStringInfoChar(buf, '(');
				get_rule_expr((Node *) iexpr->expr,
							  context, false);
				if (need_parens)
					appendStringInfoChar(buf, ')');

				context->varprefix = save_varprefix;

				if (iexpr->infercollid)
					appendStringInfo(buf, " COLLATE %s",
									 generate_collation_name(iexpr->infercollid));

				/* Add the operator class name, if not default */
				if (iexpr->inferopclass)
				{
					Oid			inferopclass = iexpr->inferopclass;
					Oid			inferopcinputtype = get_opclass_input_type(iexpr->inferopclass);

					get_opclass_name(inferopclass, inferopcinputtype, buf);
				}
			}
			break;

		case T_PartitionBoundSpec:
			{
				PartitionBoundSpec *spec = (PartitionBoundSpec *) node;
				ListCell   *cell;
				char	   *sep;

				if (spec->is_default)
				{
					appendStringInfoString(buf, "DEFAULT");
					break;
				}

				switch (spec->strategy)
				{
					case PARTITION_STRATEGY_HASH:
						Assert(spec->modulus > 0 && spec->remainder >= 0);
						Assert(spec->modulus > spec->remainder);

						appendStringInfoString(buf, "FOR VALUES");
						appendStringInfo(buf, " WITH (modulus %d, remainder %d)",
										 spec->modulus, spec->remainder);
						break;

					case PARTITION_STRATEGY_LIST:
						Assert(spec->listdatums != NIL);

						appendStringInfoString(buf, "FOR VALUES IN (");
						sep = "";
						foreach(cell, spec->listdatums)
						{
							Const	   *val = lfirst_node(Const, cell);

							appendStringInfoString(buf, sep);
							get_const_expr(val, context, -1);
							sep = ", ";
						}

						appendStringInfoChar(buf, ')');
						break;

					case PARTITION_STRATEGY_RANGE:
						Assert(spec->lowerdatums != NIL &&
							   spec->upperdatums != NIL &&
							   list_length(spec->lowerdatums) ==
							   list_length(spec->upperdatums));

						appendStringInfo(buf, "FOR VALUES FROM %s TO %s",
										 get_range_partbound_string(spec->lowerdatums),
										 get_range_partbound_string(spec->upperdatums));
						break;

					default:
						elog(ERROR, "unrecognized partition strategy: %d",
							 (int) spec->strategy);
						break;
				}
			}
			break;

		case T_List:
			{
				char	   *sep;
				ListCell   *l;

				sep = "";
				foreach(l, (List *) node)
				{
					appendStringInfoString(buf, sep);
					get_rule_expr((Node *) lfirst(l), context, showimplicit);
					sep = ", ";
				}
			}
			break;

		case T_TableFunc:
			get_tablefunc((TableFunc *) node, context, showimplicit);
			break;

		case T_CallStmt:
			get_proc_expr((CallStmt *) node, context, showimplicit);
			break;

		default:
			elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
			break;
	}
}

/*
 * get_rule_expr_toplevel		- Parse back a toplevel expression
 *
 * Same as get_rule_expr(), except that if the expr is just a Var, we pass
 * istoplevel = true not false to get_variable().  This causes whole-row Vars
 * to get printed with decoration that will prevent expansion of "*".
 * We need to use this in contexts such as ROW() and VALUES(), where the
 * parser would expand "foo.*" appearing at top level.  (In principle we'd
 * use this in get_target_list() too, but that has additional worries about
 * whether to print AS, so it needs to invoke get_variable() directly anyway.)
 */
static void
get_rule_expr_toplevel(Node *node, deparse_context *context,
					   bool showimplicit)
{
	if (node && IsA(node, Var))
		(void) get_variable((Var *) node, 0, true, context);
	else
		get_rule_expr(node, context, showimplicit);
}

/*
 * get_rule_list_toplevel		- Parse back a list of toplevel expressions
 *
 * Apply get_rule_expr_toplevel() to each element of a List.
 *
 * This adds commas between the expressions, but caller is responsible
 * for printing surrounding decoration.
 */
static void
get_rule_list_toplevel(List *lst, deparse_context *context,
					   bool showimplicit)
{
	const char *sep;
	ListCell   *lc;

	sep = "";
	foreach(lc, lst)
	{
		Node	   *e = (Node *) lfirst(lc);

		appendStringInfoString(context->buf, sep);
		get_rule_expr_toplevel(e, context, showimplicit);
		sep = ", ";
	}
}

/*
 * get_rule_expr_funccall		- Parse back a function-call expression
 *
 * Same as get_rule_expr(), except that we guarantee that the output will
 * look like a function call, or like one of the things the grammar treats as
 * equivalent to a function call (see the func_expr_windowless production).
 * This is needed in places where the grammar uses func_expr_windowless and
 * you can't substitute a parenthesized a_expr.  If what we have isn't going
 * to look like a function call, wrap it in a dummy CAST() expression, which
 * will satisfy the grammar --- and, indeed, is likely what the user wrote to
 * produce such a thing.
 */
static void
get_rule_expr_funccall(Node *node, deparse_context *context,
					   bool showimplicit)
{
	if (looks_like_function(node))
		get_rule_expr(node, context, showimplicit);
	else
	{
		StringInfo	buf = context->buf;

		appendStringInfoString(buf, "CAST(");
		/* no point in showing any top-level implicit cast */
		get_rule_expr(node, context, false);
		appendStringInfo(buf, " AS %s)",
						 format_type_with_typemod(exprType(node),
												  exprTypmod(node)));
	}
}

/*
 * Helper function to identify node types that satisfy func_expr_windowless.
 * If in doubt, "false" is always a safe answer.
 */
static bool
looks_like_function(Node *node)
{
	if (node == NULL)
		return false;			/* probably shouldn't happen */
	switch (nodeTag(node))
	{
		case T_FuncExpr:
			/* OK, unless it's going to deparse as a cast */
			return (((FuncExpr *) node)->funcformat == COERCE_EXPLICIT_CALL ||
					((FuncExpr *) node)->funcformat == COERCE_SQL_SYNTAX);
		case T_NullIfExpr:
		case T_CoalesceExpr:
		case T_MinMaxExpr:
		case T_SQLValueFunction:
		case T_XmlExpr:
			/* these are all accepted by func_expr_common_subexpr */
			return true;
		default:
			break;
	}
	return false;
}

/*
 * get_oper_expr			- Parse back an OpExpr node
 */
static void
get_oper_expr(OpExpr *expr, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Oid			opno = expr->opno;
	List	   *args = expr->args;

	if (!PRETTY_PAREN(context))
		appendStringInfoChar(buf, '(');
	if (list_length(args) == 2)
	{
		/* binary operator */
		Node	   *arg1 = (Node *) linitial(args);
		Node	   *arg2 = (Node *) lsecond(args);

		get_rule_expr_paren(arg1, context, true, (Node *) expr);
		appendStringInfo(buf, " %s ",
						 generate_operator_name(opno,
												exprType(arg1),
												exprType(arg2)));
		get_rule_expr_paren(arg2, context, true, (Node *) expr);
	}
	else
	{
		/* prefix operator */
		Node	   *arg = (Node *) linitial(args);

		appendStringInfo(buf, "%s ",
						 generate_operator_name(opno,
												InvalidOid,
												exprType(arg)));
		get_rule_expr_paren(arg, context, true, (Node *) expr);
	}
	if (!PRETTY_PAREN(context))
		appendStringInfoChar(buf, ')');
}

/*
 * get_func_expr			- Parse back a FuncExpr node
 */
static void
get_func_expr(FuncExpr *expr, deparse_context *context,
			  bool showimplicit)
{
	StringInfo	buf = context->buf;
	Oid			funcoid = expr->funcid;
	Oid			argtypes[FUNC_MAX_ARGS];
	int			nargs;
	List	   *argnames;
	bool		use_variadic;
	ListCell   *l;

	/*
	 * If the function call came from an implicit coercion, then just show the
	 * first argument --- unless caller wants to see implicit coercions.
	 */
	if (expr->funcformat == COERCE_IMPLICIT_CAST && !showimplicit)
	{
		get_rule_expr_paren((Node *) linitial(expr->args), context,
							false, (Node *) expr);
		return;
	}

	/*
	 * If the function call came from a cast, then show the first argument
	 * plus an explicit cast operation.
	 */
	if (expr->funcformat == COERCE_EXPLICIT_CAST ||
		expr->funcformat == COERCE_IMPLICIT_CAST)
	{
		Node	   *arg = linitial(expr->args);
		Oid			rettype = expr->funcresulttype;
		int32		coercedTypmod;

		/* Get the typmod if this is a length-coercion function */
		(void) exprIsLengthCoercion((Node *) expr, &coercedTypmod);

		get_coercion_expr(arg, context,
						  rettype, coercedTypmod,
						  (Node *) expr);

		return;
	}

	/*
	 * If the function was called using one of the SQL spec's random special
	 * syntaxes, try to reproduce that.  If we don't recognize the function,
	 * fall through.
	 */
	if (expr->funcformat == COERCE_SQL_SYNTAX)
	{
		if (get_func_sql_syntax(expr, context))
			return;
	}


	/*
	 * Normal function: display as proname(args).  First we need to extract
	 * the argument datatypes.
	 */
	if (list_length(expr->args) > FUNC_MAX_ARGS)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("too many arguments")));
	nargs = 0;
	argnames = NIL;
	foreach(l, expr->args)
	{
		Node	   *arg = (Node *) lfirst(l);

		if (IsA(arg, NamedArgExpr))
			argnames = lappend(argnames, ((NamedArgExpr *) arg)->name);
		argtypes[nargs] = exprType(arg);
		nargs++;
	}

	appendStringInfo(buf, "%s(",
					 generate_function_name(funcoid, nargs,
											argnames, argtypes,
											expr->funcvariadic,
											&use_variadic,
											context->special_exprkind));
	nargs = 0;
	foreach(l, expr->args)
	{
		if (nargs++ > 0)
			appendStringInfoString(buf, ", ");
		if (use_variadic && lnext(expr->args, l) == NULL)
			appendStringInfoString(buf, "VARIADIC ");
		get_rule_expr((Node *) lfirst(l), context, true);
	}

	appendStringInfoChar(buf, ')');
}

/*
 * get_proc_expr			- Parse back a CallStmt node
 */
static void
get_proc_expr(CallStmt *stmt, deparse_context *context,
			  bool showimplicit)
{
	StringInfo buf = context->buf;
	Oid        functionOid = stmt->funcexpr->funcid;
	bool       use_variadic;
	Oid        *argumentTypes;
	List       *finalArgumentList = NIL;
	ListCell   *argumentCell;
	List       *namedArgList = NIL;
	int        numberOfArgs = -1;

	if (!get_merged_argument_list(stmt, &namedArgList, &argumentTypes,
										&finalArgumentList, &numberOfArgs))
	{
		/* Nothing merged i.e. no OUT arguments */
		get_func_expr((FuncExpr *) stmt->funcexpr, context, showimplicit);
		return;
	}

	appendStringInfo(buf, "%s(",
					 generate_function_name(functionOid, numberOfArgs,
										namedArgList, argumentTypes,
										stmt->funcexpr->funcvariadic,
										&use_variadic,
										context->special_exprkind));
	int argNumber = 0;
	foreach(argumentCell, finalArgumentList)
	{
		if (argNumber++ > 0)
			appendStringInfoString(buf, ", ");
		if (use_variadic && lnext(finalArgumentList, argumentCell) == NULL)
			appendStringInfoString(buf, "VARIADIC ");
		get_rule_expr((Node *) lfirst(argumentCell), context, true);
		argNumber++;
	}

	appendStringInfoChar(buf, ')');
}

/*
 * get_agg_expr			- Parse back an Aggref node
 */
static void
get_agg_expr(Aggref *aggref, deparse_context *context,
			 Aggref *original_aggref)
{
	StringInfo	buf = context->buf;
	Oid			argtypes[FUNC_MAX_ARGS];
	int			nargs;
	bool use_variadic;

	/*
	 * For a combining aggregate, we look up and deparse the corresponding
	 * partial aggregate instead.  This is necessary because our input
	 * argument list has been replaced; the new argument list always has just
	 * one element, which will point to a partial Aggref that supplies us with
	 * transition states to combine.
	 */
	if (DO_AGGSPLIT_COMBINE(aggref->aggsplit))
	{
		TargetEntry *tle;


		Assert(list_length(aggref->args) == 1);
		tle = linitial_node(TargetEntry, aggref->args);
		resolve_special_varno((Node *) tle->expr, context,
							  get_agg_combine_expr, original_aggref);
		return;
	}

	/*
	 * Mark as PARTIAL, if appropriate.  We look to the original aggref so as
	 * to avoid printing this when recursing from the code just above.
	 */
	if (DO_AGGSPLIT_SKIPFINAL(original_aggref->aggsplit))
		appendStringInfoString(buf, "PARTIAL ");

	/* Extract the argument types as seen by the parser */
	nargs = get_aggregate_argtypes(aggref, argtypes);

	/* Print the aggregate name, schema-qualified if needed */
	appendStringInfo(buf, "%s(%s",
					 generate_function_name(aggref->aggfnoid, nargs,
											NIL, argtypes,
											aggref->aggvariadic,
											&use_variadic,
											context->special_exprkind),
					 (aggref->aggdistinct != NIL) ? "DISTINCT " : "");

	if (AGGKIND_IS_ORDERED_SET(aggref->aggkind))
	{
		/*
		 * Ordered-set aggregates do not use "*" syntax.  Also, we needn't
		 * worry about inserting VARIADIC.  So we can just dump the direct
		 * args as-is.
		 */
		Assert(!aggref->aggvariadic);
		get_rule_expr((Node *) aggref->aggdirectargs, context, true);
		Assert(aggref->aggorder != NIL);
		appendStringInfoString(buf, ") WITHIN GROUP (ORDER BY ");
		get_rule_orderby(aggref->aggorder, aggref->args, false, context);
	}
	else
	{
		/* aggstar can be set only in zero-argument aggregates */
		if (aggref->aggstar)
			appendStringInfoChar(buf, '*');
		else
		{
			ListCell   *l;
			int			i;

			i = 0;
			foreach(l, aggref->args)
			{
				TargetEntry *tle = (TargetEntry *) lfirst(l);
				Node	   *arg = (Node *) tle->expr;

				Assert(!IsA(arg, NamedArgExpr));
				if (tle->resjunk)
					continue;
				if (i++ > 0)
					appendStringInfoString(buf, ", ");
				if (use_variadic && i == nargs)
					appendStringInfoString(buf, "VARIADIC ");
				get_rule_expr(arg, context, true);
			}
		}

		if (aggref->aggorder != NIL)
		{
			appendStringInfoString(buf, " ORDER BY ");
			get_rule_orderby(aggref->aggorder, aggref->args, false, context);
		}
	}

	if (aggref->aggfilter != NULL)
	{
		appendStringInfoString(buf, ") FILTER (WHERE ");
		get_rule_expr((Node *) aggref->aggfilter, context, false);
	}

	appendStringInfoChar(buf, ')');
}

/*
 * This is a helper function for get_agg_expr().  It's used when we deparse
 * a combining Aggref; resolve_special_varno locates the corresponding partial
 * Aggref and then calls this.
 */
static void
get_agg_combine_expr(Node *node, deparse_context *context, void *callback_arg)
{
	Aggref	   *aggref;
	Aggref	   *original_aggref = callback_arg;

	if (!IsA(node, Aggref))
		elog(ERROR, "combining Aggref does not point to an Aggref");

	aggref = (Aggref *) node;
	get_agg_expr(aggref, context, original_aggref);
}

/*
 * get_windowfunc_expr	- Parse back a WindowFunc node
 */
static void
get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Oid			argtypes[FUNC_MAX_ARGS];
	int			nargs;
	List	   *argnames;
	ListCell   *l;

	if (list_length(wfunc->args) > FUNC_MAX_ARGS)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("too many arguments")));
	nargs = 0;
	argnames = NIL;
	foreach(l, wfunc->args)
	{
		Node	   *arg = (Node *) lfirst(l);

		if (IsA(arg, NamedArgExpr))
			argnames = lappend(argnames, ((NamedArgExpr *) arg)->name);
		argtypes[nargs] = exprType(arg);
		nargs++;
	}

	appendStringInfo(buf, "%s(",
					 generate_function_name(wfunc->winfnoid, nargs,
											argnames, argtypes,
											false, NULL,
											context->special_exprkind));

	/* winstar can be set only in zero-argument aggregates */
	if (wfunc->winstar)
		appendStringInfoChar(buf, '*');
	else
		get_rule_expr((Node *) wfunc->args, context, true);

	if (wfunc->aggfilter != NULL)
	{
		appendStringInfoString(buf, ") FILTER (WHERE ");
		get_rule_expr((Node *) wfunc->aggfilter, context, false);
	}

	appendStringInfoString(buf, ") OVER ");

	foreach(l, context->windowClause)
	{
		WindowClause *wc = (WindowClause *) lfirst(l);

		if (wc->winref == wfunc->winref)
		{
			if (wc->name)
				appendStringInfoString(buf, quote_identifier(wc->name));
			else
				get_rule_windowspec(wc, context->windowTList, context);
			break;
		}
	}
	if (l == NULL)
	{
		if (context->windowClause)
			elog(ERROR, "could not find window clause for winref %u",
				 wfunc->winref);

		/*
		 * In EXPLAIN, we don't have window context information available, so
		 * we have to settle for this:
		 */
		appendStringInfoString(buf, "(?)");
	}
}

/*
 * get_func_sql_syntax		- Parse back a SQL-syntax function call
 *
 * Returns true if we successfully deparsed, false if we did not
 * recognize the function.
 */
static bool
get_func_sql_syntax(FuncExpr *expr, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Oid			funcoid = expr->funcid;

	switch (funcoid)
	{
		case F_TIMEZONE_INTERVAL_TIMESTAMP:
		case F_TIMEZONE_INTERVAL_TIMESTAMPTZ:
		case F_TIMEZONE_INTERVAL_TIMETZ:
		case F_TIMEZONE_TEXT_TIMESTAMP:
		case F_TIMEZONE_TEXT_TIMESTAMPTZ:
		case F_TIMEZONE_TEXT_TIMETZ:
			/* AT TIME ZONE ... note reversed argument order */
			appendStringInfoChar(buf, '(');
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			appendStringInfoString(buf, " AT TIME ZONE ");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoChar(buf, ')');
			return true;

		case F_OVERLAPS_TIMESTAMPTZ_INTERVAL_TIMESTAMPTZ_INTERVAL:
		case F_OVERLAPS_TIMESTAMPTZ_INTERVAL_TIMESTAMPTZ_TIMESTAMPTZ:
		case F_OVERLAPS_TIMESTAMPTZ_TIMESTAMPTZ_TIMESTAMPTZ_INTERVAL:
		case F_OVERLAPS_TIMESTAMPTZ_TIMESTAMPTZ_TIMESTAMPTZ_TIMESTAMPTZ:
		case F_OVERLAPS_TIMESTAMP_INTERVAL_TIMESTAMP_INTERVAL:
		case F_OVERLAPS_TIMESTAMP_INTERVAL_TIMESTAMP_TIMESTAMP:
		case F_OVERLAPS_TIMESTAMP_TIMESTAMP_TIMESTAMP_INTERVAL:
		case F_OVERLAPS_TIMESTAMP_TIMESTAMP_TIMESTAMP_TIMESTAMP:
		case F_OVERLAPS_TIMETZ_TIMETZ_TIMETZ_TIMETZ:
		case F_OVERLAPS_TIME_INTERVAL_TIME_INTERVAL:
		case F_OVERLAPS_TIME_INTERVAL_TIME_TIME:
		case F_OVERLAPS_TIME_TIME_TIME_INTERVAL:
		case F_OVERLAPS_TIME_TIME_TIME_TIME:
			/* (x1, x2) OVERLAPS (y1, y2) */
			appendStringInfoString(buf, "((");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoString(buf, ", ");
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			appendStringInfoString(buf, ") OVERLAPS (");
			get_rule_expr((Node *) lthird(expr->args), context, false);
			appendStringInfoString(buf, ", ");
			get_rule_expr((Node *) lfourth(expr->args), context, false);
			appendStringInfoString(buf, "))");
			return true;

		case F_EXTRACT_TEXT_DATE:
		case F_EXTRACT_TEXT_TIME:
		case F_EXTRACT_TEXT_TIMETZ:
		case F_EXTRACT_TEXT_TIMESTAMP:
		case F_EXTRACT_TEXT_TIMESTAMPTZ:
		case F_EXTRACT_TEXT_INTERVAL:
			/* EXTRACT (x FROM y) */
			appendStringInfoString(buf, "EXTRACT(");
			{
				Const	   *con = (Const *) linitial(expr->args);

				Assert(IsA(con, Const) &&
					   con->consttype == TEXTOID &&
					   !con->constisnull);
				appendStringInfoString(buf, TextDatumGetCString(con->constvalue));
			}
			appendStringInfoString(buf, " FROM ");
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			appendStringInfoChar(buf, ')');
			return true;

		case F_IS_NORMALIZED:
			/* IS xxx NORMALIZED */
			appendStringInfoString(buf, "((");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoString(buf, ") IS");
			if (list_length(expr->args) == 2)
			{
				Const	   *con = (Const *) lsecond(expr->args);

				Assert(IsA(con, Const) &&
					   con->consttype == TEXTOID &&
					   !con->constisnull);
				appendStringInfo(buf, " %s",
								 TextDatumGetCString(con->constvalue));
			}
			appendStringInfoString(buf, " NORMALIZED)");
			return true;

		case F_PG_COLLATION_FOR:
			/* COLLATION FOR */
			appendStringInfoString(buf, "COLLATION FOR (");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoChar(buf, ')');
			return true;

			/*
			 * XXX EXTRACT, a/k/a date_part(), is intentionally not covered
			 * yet.  Add it after we change the return type to numeric.
			 */

		case F_NORMALIZE:
			/* NORMALIZE() */
			appendStringInfoString(buf, "NORMALIZE(");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			if (list_length(expr->args) == 2)
			{
				Const	   *con = (Const *) lsecond(expr->args);

				Assert(IsA(con, Const) &&
					   con->consttype == TEXTOID &&
					   !con->constisnull);
				appendStringInfo(buf, ", %s",
								 TextDatumGetCString(con->constvalue));
			}
			appendStringInfoChar(buf, ')');
			return true;

		case F_OVERLAY_BIT_BIT_INT4:
		case F_OVERLAY_BIT_BIT_INT4_INT4:
		case F_OVERLAY_BYTEA_BYTEA_INT4:
		case F_OVERLAY_BYTEA_BYTEA_INT4_INT4:
		case F_OVERLAY_TEXT_TEXT_INT4:
		case F_OVERLAY_TEXT_TEXT_INT4_INT4:
			/* OVERLAY() */
			appendStringInfoString(buf, "OVERLAY(");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoString(buf, " PLACING ");
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			appendStringInfoString(buf, " FROM ");
			get_rule_expr((Node *) lthird(expr->args), context, false);
			if (list_length(expr->args) == 4)
			{
				appendStringInfoString(buf, " FOR ");
				get_rule_expr((Node *) lfourth(expr->args), context, false);
			}
			appendStringInfoChar(buf, ')');
			return true;

		case F_POSITION_BIT_BIT:
		case F_POSITION_BYTEA_BYTEA:
		case F_POSITION_TEXT_TEXT:
			/* POSITION() ... extra parens since args are b_expr not a_expr */
			appendStringInfoString(buf, "POSITION((");
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			appendStringInfoString(buf, ") IN (");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoString(buf, "))");
			return true;

		case F_SUBSTRING_BIT_INT4:
		case F_SUBSTRING_BIT_INT4_INT4:
		case F_SUBSTRING_BYTEA_INT4:
		case F_SUBSTRING_BYTEA_INT4_INT4:
		case F_SUBSTRING_TEXT_INT4:
		case F_SUBSTRING_TEXT_INT4_INT4:
			/* SUBSTRING FROM/FOR (i.e., integer-position variants) */
			appendStringInfoString(buf, "SUBSTRING(");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoString(buf, " FROM ");
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			if (list_length(expr->args) == 3)
			{
				appendStringInfoString(buf, " FOR ");
				get_rule_expr((Node *) lthird(expr->args), context, false);
			}
			appendStringInfoChar(buf, ')');
			return true;

		case F_SUBSTRING_TEXT_TEXT_TEXT:
			/* SUBSTRING SIMILAR/ESCAPE */
			appendStringInfoString(buf, "SUBSTRING(");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoString(buf, " SIMILAR ");
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			appendStringInfoString(buf, " ESCAPE ");
			get_rule_expr((Node *) lthird(expr->args), context, false);
			appendStringInfoChar(buf, ')');
			return true;

		case F_BTRIM_BYTEA_BYTEA:
		case F_BTRIM_TEXT:
		case F_BTRIM_TEXT_TEXT:
			/* TRIM() */
			appendStringInfoString(buf, "TRIM(BOTH");
			if (list_length(expr->args) == 2)
			{
				appendStringInfoChar(buf, ' ');
				get_rule_expr((Node *) lsecond(expr->args), context, false);
			}
			appendStringInfoString(buf, " FROM ");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoChar(buf, ')');
			return true;

		case F_LTRIM_BYTEA_BYTEA:
		case F_LTRIM_TEXT:
		case F_LTRIM_TEXT_TEXT:
			/* TRIM() */
			appendStringInfoString(buf, "TRIM(LEADING");
			if (list_length(expr->args) == 2)
			{
				appendStringInfoChar(buf, ' ');
				get_rule_expr((Node *) lsecond(expr->args), context, false);
			}
			appendStringInfoString(buf, " FROM ");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoChar(buf, ')');
			return true;

		case F_RTRIM_BYTEA_BYTEA:
		case F_RTRIM_TEXT:
		case F_RTRIM_TEXT_TEXT:
			/* TRIM() */
			appendStringInfoString(buf, "TRIM(TRAILING");
			if (list_length(expr->args) == 2)
			{
				appendStringInfoChar(buf, ' ');
				get_rule_expr((Node *) lsecond(expr->args), context, false);
			}
			appendStringInfoString(buf, " FROM ");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoChar(buf, ')');
			return true;

		case F_XMLEXISTS:
			/* XMLEXISTS ... extra parens because args are c_expr */
			appendStringInfoString(buf, "XMLEXISTS((");
			get_rule_expr((Node *) linitial(expr->args), context, false);
			appendStringInfoString(buf, ") PASSING (");
			get_rule_expr((Node *) lsecond(expr->args), context, false);
			appendStringInfoString(buf, "))");
			return true;
	}
	return false;
}

/* ----------
 * get_coercion_expr
 *
 *	Make a string representation of a value coerced to a specific type
 * ----------
 */
static void
get_coercion_expr(Node *arg, deparse_context *context,
				  Oid resulttype, int32 resulttypmod,
				  Node *parentNode)
{
	StringInfo	buf = context->buf;

	/*
	 * Since parse_coerce.c doesn't immediately collapse application of
	 * length-coercion functions to constants, what we'll typically see in
	 * such cases is a Const with typmod -1 and a length-coercion function
	 * right above it.  Avoid generating redundant output. However, beware of
	 * suppressing casts when the user actually wrote something like
	 * 'foo'::text::char(3).
	 *
	 * Note: it might seem that we are missing the possibility of needing to
	 * print a COLLATE clause for such a Const.  However, a Const could only
	 * have nondefault collation in a post-constant-folding tree, in which the
	 * length coercion would have been folded too.  See also the special
	 * handling of CollateExpr in coerce_to_target_type(): any collation
	 * marking will be above the coercion node, not below it.
	 */
	if (arg && IsA(arg, Const) &&
		((Const *) arg)->consttype == resulttype &&
		((Const *) arg)->consttypmod == -1)
	{
		/* Show the constant without normal ::typename decoration */
		get_const_expr((Const *) arg, context, -1);
	}
	else
	{
		if (!PRETTY_PAREN(context))
			appendStringInfoChar(buf, '(');
		get_rule_expr_paren(arg, context, false, parentNode);
		if (!PRETTY_PAREN(context))
			appendStringInfoChar(buf, ')');
	}
	appendStringInfo(buf, "::%s",
					 format_type_with_typemod(resulttype, resulttypmod));
}

/* ----------
 * get_const_expr
 *
 *	Make a string representation of a Const
 *
 * showtype can be -1 to never show "::typename" decoration, or +1 to always
 * show it, or 0 to show it only if the constant wouldn't be assumed to be
 * the right type by default.
 *
 * If the Const's collation isn't default for its type, show that too.
 * We mustn't do this when showtype is -1 (since that means the caller will
 * print "::typename", and we can't put a COLLATE clause in between).  It's
 * caller's responsibility that collation isn't missed in such cases.
 * ----------
 */
static void
get_const_expr(Const *constval, deparse_context *context, int showtype)
{
	StringInfo	buf = context->buf;
	Oid			typoutput;
	bool		typIsVarlena;
	char	   *extval;
	bool		needlabel = false;

	if (constval->constisnull)
	{
		/*
		 * Always label the type of a NULL constant to prevent misdecisions
		 * about type when reparsing.
		 */
		appendStringInfoString(buf, "NULL");
		if (showtype >= 0)
		{
			appendStringInfo(buf, "::%s",
							 format_type_with_typemod(constval->consttype,
													  constval->consttypmod));
			get_const_collation(constval, context);
		}
		return;
	}

	getTypeOutputInfo(constval->consttype,
					  &typoutput, &typIsVarlena);

	extval = OidOutputFunctionCall(typoutput, constval->constvalue);

	switch (constval->consttype)
	{
		case INT4OID:

			/*
			 * INT4 can be printed without any decoration, unless it is
			 * negative; in that case print it as '-nnn'::integer to ensure
			 * that the output will re-parse as a constant, not as a constant
			 * plus operator.  In most cases we could get away with printing
			 * (-nnn) instead, because of the way that gram.y handles negative
			 * literals; but that doesn't work for INT_MIN, and it doesn't
			 * seem that much prettier anyway.
			 */
			if (extval[0] != '-')
				appendStringInfoString(buf, extval);
			else
			{
				appendStringInfo(buf, "'%s'", extval);
				needlabel = true;	/* we must attach a cast */
			}
			break;

		case NUMERICOID:

			/*
			 * NUMERIC can be printed without quotes if it looks like a float
			 * constant (not an integer, and not Infinity or NaN) and doesn't
			 * have a leading sign (for the same reason as for INT4).
			 */
			if (isdigit((unsigned char) extval[0]) &&
				strcspn(extval, "eE.") != strlen(extval))
			{
				appendStringInfoString(buf, extval);
			}
			else
			{
				appendStringInfo(buf, "'%s'", extval);
				needlabel = true;	/* we must attach a cast */
			}
			break;

		case BITOID:
		case VARBITOID:
			appendStringInfo(buf, "B'%s'", extval);
			break;

		case BOOLOID:
			if (strcmp(extval, "t") == 0)
				appendStringInfoString(buf, "true");
			else
				appendStringInfoString(buf, "false");
			break;

		default:
			simple_quote_literal(buf, extval);
			break;
	}

	pfree(extval);

	if (showtype < 0)
		return;

	/*
	 * For showtype == 0, append ::typename unless the constant will be
	 * implicitly typed as the right type when it is read in.
	 *
	 * XXX this code has to be kept in sync with the behavior of the parser,
	 * especially make_const.
	 */
	switch (constval->consttype)
	{
		case BOOLOID:
		case UNKNOWNOID:
			/* These types can be left unlabeled */
			needlabel = false;
			break;
		case INT4OID:
			/* We determined above whether a label is needed */
			break;
		case NUMERICOID:

			/*
			 * Float-looking constants will be typed as numeric, which we
			 * checked above; but if there's a nondefault typmod we need to
			 * show it.
			 */
			needlabel |= (constval->consttypmod >= 0);
			break;
		default:
			needlabel = true;
			break;
	}
	if (needlabel || showtype > 0)
		appendStringInfo(buf, "::%s",
						 format_type_with_typemod(constval->consttype,
												  constval->consttypmod));

	get_const_collation(constval, context);
}

/*
 * helper for get_const_expr: append COLLATE if needed
 */
static void
get_const_collation(Const *constval, deparse_context *context)
{
	StringInfo	buf = context->buf;

	if (OidIsValid(constval->constcollid))
	{
		Oid			typcollation = get_typcollation(constval->consttype);

		if (constval->constcollid != typcollation)
		{
			appendStringInfo(buf, " COLLATE %s",
							 generate_collation_name(constval->constcollid));
		}
	}
}

/*
 * simple_quote_literal - Format a string as a SQL literal, append to buf
 */
static void
simple_quote_literal(StringInfo buf, const char *val)
{
	const char *valptr;

	/*
	 * We form the string literal according to the prevailing setting of
	 * standard_conforming_strings; we never use E''. User is responsible for
	 * making sure result is used correctly.
	 */
	appendStringInfoChar(buf, '\'');
	for (valptr = val; *valptr; valptr++)
	{
		char		ch = *valptr;

		if (SQL_STR_DOUBLE(ch, !standard_conforming_strings))
			appendStringInfoChar(buf, ch);
		appendStringInfoChar(buf, ch);
	}
	appendStringInfoChar(buf, '\'');
}

/* ----------
 * get_sublink_expr			- Parse back a sublink
 * ----------
 */
static void
get_sublink_expr(SubLink *sublink, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Query	   *query = (Query *) (sublink->subselect);
	char	   *opname = NULL;
	bool		need_paren;

	if (sublink->subLinkType == ARRAY_SUBLINK)
		appendStringInfoString(buf, "ARRAY(");
	else
		appendStringInfoChar(buf, '(');

	/*
	 * Note that we print the name of only the first operator, when there are
	 * multiple combining operators.  This is an approximation that could go
	 * wrong in various scenarios (operators in different schemas, renamed
	 * operators, etc) but there is not a whole lot we can do about it, since
	 * the syntax allows only one operator to be shown.
	 */
	if (sublink->testexpr)
	{
		if (IsA(sublink->testexpr, OpExpr))
		{
			/* single combining operator */
			OpExpr	   *opexpr = (OpExpr *) sublink->testexpr;

			get_rule_expr(linitial(opexpr->args), context, true);
			opname = generate_operator_name(opexpr->opno,
											exprType(linitial(opexpr->args)),
											exprType(lsecond(opexpr->args)));
		}
		else if (IsA(sublink->testexpr, BoolExpr))
		{
			/* multiple combining operators, = or <> cases */
			char	   *sep;
			ListCell   *l;

			appendStringInfoChar(buf, '(');
			sep = "";
			foreach(l, ((BoolExpr *) sublink->testexpr)->args)
			{
				OpExpr	   *opexpr = lfirst_node(OpExpr, l);

				appendStringInfoString(buf, sep);
				get_rule_expr(linitial(opexpr->args), context, true);
				if (!opname)
					opname = generate_operator_name(opexpr->opno,
													exprType(linitial(opexpr->args)),
													exprType(lsecond(opexpr->args)));
				sep = ", ";
			}
			appendStringInfoChar(buf, ')');
		}
		else if (IsA(sublink->testexpr, RowCompareExpr))
		{
			/* multiple combining operators, < <= > >= cases */
			RowCompareExpr *rcexpr = (RowCompareExpr *) sublink->testexpr;

			appendStringInfoChar(buf, '(');
			get_rule_expr((Node *) rcexpr->largs, context, true);
			opname = generate_operator_name(linitial_oid(rcexpr->opnos),
											exprType(linitial(rcexpr->largs)),
											exprType(linitial(rcexpr->rargs)));
			appendStringInfoChar(buf, ')');
		}
		else
			elog(ERROR, "unrecognized testexpr type: %d",
				 (int) nodeTag(sublink->testexpr));
	}

	need_paren = true;

	switch (sublink->subLinkType)
	{
		case EXISTS_SUBLINK:
			appendStringInfoString(buf, "EXISTS ");
			break;

		case ANY_SUBLINK:
			if (strcmp(opname, "=") == 0)	/* Represent = ANY as IN */
				appendStringInfoString(buf, " IN ");
			else
				appendStringInfo(buf, " %s ANY ", opname);
			break;

		case ALL_SUBLINK:
			appendStringInfo(buf, " %s ALL ", opname);
			break;

		case ROWCOMPARE_SUBLINK:
			appendStringInfo(buf, " %s ", opname);
			break;

		case EXPR_SUBLINK:
		case MULTIEXPR_SUBLINK:
		case ARRAY_SUBLINK:
			need_paren = false;
			break;

		case CTE_SUBLINK:		/* shouldn't occur in a SubLink */
		default:
			elog(ERROR, "unrecognized sublink type: %d",
				 (int) sublink->subLinkType);
			break;
	}

	if (need_paren)
		appendStringInfoChar(buf, '(');

	get_query_def(query, buf, context->namespaces, NULL, false,
				  context->prettyFlags, context->wrapColumn,
				  context->indentLevel);

	if (need_paren)
		appendStringInfoString(buf, "))");
	else
		appendStringInfoChar(buf, ')');
}

/* ----------
 * get_tablefunc			- Parse back a table function
 * ----------
 */
static void
get_tablefunc(TableFunc *tf, deparse_context *context, bool showimplicit)
{
	StringInfo	buf = context->buf;

	/* XMLTABLE is the only existing implementation. */

	appendStringInfoString(buf, "XMLTABLE(");

	if (tf->ns_uris != NIL)
	{
		ListCell   *lc1,
				   *lc2;
		bool		first = true;

		appendStringInfoString(buf, "XMLNAMESPACES (");
		forboth(lc1, tf->ns_uris, lc2, tf->ns_names)
		{
			Node	   *expr = (Node *) lfirst(lc1);
			char	   *name = strVal(lfirst(lc2));

			if (!first)
				appendStringInfoString(buf, ", ");
			else
				first = false;

			if (name != NULL)
			{
				get_rule_expr(expr, context, showimplicit);
				appendStringInfo(buf, " AS %s", name);
			}
			else
			{
				appendStringInfoString(buf, "DEFAULT ");
				get_rule_expr(expr, context, showimplicit);
			}
		}
		appendStringInfoString(buf, "), ");
	}

	appendStringInfoChar(buf, '(');
	get_rule_expr((Node *) tf->rowexpr, context, showimplicit);
	appendStringInfoString(buf, ") PASSING (");
	get_rule_expr((Node *) tf->docexpr, context, showimplicit);
	appendStringInfoChar(buf, ')');

	if (tf->colexprs != NIL)
	{
		ListCell   *l1;
		ListCell   *l2;
		ListCell   *l3;
		ListCell   *l4;
		ListCell   *l5;
		int			colnum = 0;

		appendStringInfoString(buf, " COLUMNS ");
		forfive(l1, tf->colnames, l2, tf->coltypes, l3, tf->coltypmods,
				l4, tf->colexprs, l5, tf->coldefexprs)
		{
			char	   *colname = strVal(lfirst(l1));
			Oid			typid = lfirst_oid(l2);
			int32		typmod = lfirst_int(l3);
			Node	   *colexpr = (Node *) lfirst(l4);
			Node	   *coldefexpr = (Node *) lfirst(l5);
			bool		ordinality = (tf->ordinalitycol == colnum);
			bool		notnull = bms_is_member(colnum, tf->notnulls);

			if (colnum > 0)
				appendStringInfoString(buf, ", ");
			colnum++;

			appendStringInfo(buf, "%s %s", quote_identifier(colname),
							 ordinality ? "FOR ORDINALITY" :
							 format_type_with_typemod(typid, typmod));
			if (ordinality)
				continue;

			if (coldefexpr != NULL)
			{
				appendStringInfoString(buf, " DEFAULT (");
				get_rule_expr((Node *) coldefexpr, context, showimplicit);
				appendStringInfoChar(buf, ')');
			}
			if (colexpr != NULL)
			{
				appendStringInfoString(buf, " PATH (");
				get_rule_expr((Node *) colexpr, context, showimplicit);
				appendStringInfoChar(buf, ')');
			}
			if (notnull)
				appendStringInfoString(buf, " NOT NULL");
		}
	}

	appendStringInfoChar(buf, ')');
}

/* ----------
 * get_from_clause			- Parse back a FROM clause
 *
 * "prefix" is the keyword that denotes the start of the list of FROM
 * elements. It is FROM when used to parse back SELECT and UPDATE, but
 * is USING when parsing back DELETE.
 * ----------
 */
static void
get_from_clause(Query *query, const char *prefix, deparse_context *context)
{
	StringInfo	buf = context->buf;
	bool		first = true;
	ListCell   *l;

	/*
	 * We use the query's jointree as a guide to what to print.  However, we
	 * must ignore auto-added RTEs that are marked not inFromCl. (These can
	 * only appear at the top level of the jointree, so it's sufficient to
	 * check here.)  This check also ensures we ignore the rule pseudo-RTEs
	 * for NEW and OLD.
	 */
	foreach(l, query->jointree->fromlist)
	{
		Node	   *jtnode = (Node *) lfirst(l);

		if (IsA(jtnode, RangeTblRef))
		{
			int			varno = ((RangeTblRef *) jtnode)->rtindex;
			RangeTblEntry *rte = rt_fetch(varno, query->rtable);

			if (!rte->inFromCl)
				continue;
		}

		if (first)
		{
			appendContextKeyword(context, prefix,
								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 2);
			first = false;

			get_from_clause_item(jtnode, query, context);
		}
		else
		{
			StringInfoData itembuf;

			appendStringInfoString(buf, ", ");

			/*
			 * Put the new FROM item's text into itembuf so we can decide
			 * after we've got it whether or not it needs to go on a new line.
			 */
			initStringInfo(&itembuf);
			context->buf = &itembuf;

			get_from_clause_item(jtnode, query, context);

			/* Restore context's output buffer */
			context->buf = buf;

			/* Consider line-wrapping if enabled */
			if (PRETTY_INDENT(context) && context->wrapColumn >= 0)
			{
				/* Does the new item start with a new line? */
				if (itembuf.len > 0 && itembuf.data[0] == '\n')
				{
					/* If so, we shouldn't add anything */
					/* instead, remove any trailing spaces currently in buf */
					removeStringInfoSpaces(buf);
				}
				else
				{
					char	   *trailing_nl;

					/* Locate the start of the current line in the buffer */
					trailing_nl = strrchr(buf->data, '\n');
					if (trailing_nl == NULL)
						trailing_nl = buf->data;
					else
						trailing_nl++;

					/*
					 * Add a newline, plus some indentation, if the new item
					 * would cause an overflow.
					 */
					if (strlen(trailing_nl) + itembuf.len > context->wrapColumn)
						appendContextKeyword(context, "", -PRETTYINDENT_STD,
											 PRETTYINDENT_STD,
											 PRETTYINDENT_VAR);
				}
			}

			/* Add the new item */
			appendStringInfoString(buf, itembuf.data);

			/* clean up */
			pfree(itembuf.data);
		}
	}
}

static void
get_from_clause_item(Node *jtnode, Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	deparse_namespace *dpns = (deparse_namespace *) linitial(context->namespaces);

	if (IsA(jtnode, RangeTblRef))
	{
		int			varno = ((RangeTblRef *) jtnode)->rtindex;
		RangeTblEntry *rte = rt_fetch(varno, query->rtable);
		char	   *refname = get_rtable_name(varno, context);
		deparse_columns *colinfo = deparse_columns_fetch(varno, dpns);
		RangeTblFunction *rtfunc1 = NULL;
		bool		printalias;
		CitusRTEKind rteKind = GetRangeTblKind(rte);

		if (rte->lateral)
			appendStringInfoString(buf, "LATERAL ");

		/* Print the FROM item proper */
		switch (rte->rtekind)
		{
			case RTE_RELATION:
				/* Normal relation RTE */
				appendStringInfo(buf, "%s%s",
								 only_marker(rte),
								 generate_relation_or_shard_name(rte->relid,
																 context->distrelid,
																 context->shardid,
																 context->namespaces));
				break;
			case RTE_SUBQUERY:
				/* Subquery RTE */
				appendStringInfoChar(buf, '(');
				get_query_def(rte->subquery, buf, context->namespaces, NULL,
				              true,
							  context->prettyFlags, context->wrapColumn,
							  context->indentLevel);
				appendStringInfoChar(buf, ')');
				break;
			case RTE_FUNCTION:
				/* if it's a shard, do differently */
				if (GetRangeTblKind(rte) == CITUS_RTE_SHARD)
				{
					char *fragmentSchemaName = NULL;
					char *fragmentTableName = NULL;

					ExtractRangeTblExtraData(rte, NULL, &fragmentSchemaName, &fragmentTableName, NULL);

					/* use schema and table name from the remote alias */
					appendStringInfo(buf, "%s%s",
									 only_marker(rte),
									 generate_fragment_name(fragmentSchemaName,
															fragmentTableName));
					break;
				}

				/* Function RTE */
				rtfunc1 = (RangeTblFunction *) linitial(rte->functions);

				/*
				 * Omit ROWS FROM() syntax for just one function, unless it
				 * has both a coldeflist and WITH ORDINALITY. If it has both,
				 * we must use ROWS FROM() syntax to avoid ambiguity about
				 * whether the coldeflist includes the ordinality column.
				 */
				if (list_length(rte->functions) == 1 &&
					(rtfunc1->funccolnames == NIL || !rte->funcordinality))
				{
					get_rule_expr_funccall(rtfunc1->funcexpr, context, true);
					/* we'll print the coldeflist below, if it has one */
				}
				else
				{
					bool		all_unnest;
					ListCell   *lc;

					/*
					 * If all the function calls in the list are to unnest,
					 * and none need a coldeflist, then collapse the list back
					 * down to UNNEST(args).  (If we had more than one
					 * built-in unnest function, this would get more
					 * difficult.)
					 *
					 * XXX This is pretty ugly, since it makes not-terribly-
					 * future-proof assumptions about what the parser would do
					 * with the output; but the alternative is to emit our
					 * nonstandard ROWS FROM() notation for what might have
					 * been a perfectly spec-compliant multi-argument
					 * UNNEST().
					 */
					all_unnest = true;
					foreach(lc, rte->functions)
					{
						RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);

						if (!IsA(rtfunc->funcexpr, FuncExpr) ||
							((FuncExpr *) rtfunc->funcexpr)->funcid != F_UNNEST_ANYARRAY ||
							rtfunc->funccolnames != NIL)
						{
							all_unnest = false;
							break;
						}
					}

					if (all_unnest)
					{
						List	   *allargs = NIL;

						foreach(lc, rte->functions)
						{
							RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
							List	   *args = ((FuncExpr *) rtfunc->funcexpr)->args;

							allargs = list_concat(allargs, args);
						}

						appendStringInfoString(buf, "UNNEST(");
						get_rule_expr((Node *) allargs, context, true);
						appendStringInfoChar(buf, ')');
					}
					else
					{
						int			funcno = 0;

						appendStringInfoString(buf, "ROWS FROM(");
						foreach(lc, rte->functions)
						{
							RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);

							if (funcno > 0)
								appendStringInfoString(buf, ", ");
							get_rule_expr_funccall(rtfunc->funcexpr, context, true);
							if (rtfunc->funccolnames != NIL)
							{
								/* Reconstruct the column definition list */
								appendStringInfoString(buf, " AS ");
								get_from_clause_coldeflist(rtfunc,
														   NULL,
														   context);
							}
							funcno++;
						}
						appendStringInfoChar(buf, ')');
					}
					/* prevent printing duplicate coldeflist below */
					rtfunc1 = NULL;
				}
				if (rte->funcordinality)
					appendStringInfoString(buf, " WITH ORDINALITY");
				break;
			case RTE_TABLEFUNC:
				get_tablefunc(rte->tablefunc, context, true);
				break;
			case RTE_VALUES:
				/* Values list RTE */
				appendStringInfoChar(buf, '(');
				get_values_def(rte->values_lists, context);
				appendStringInfoChar(buf, ')');
				break;
			case RTE_CTE:
				appendStringInfoString(buf, quote_identifier(rte->ctename));
				break;
			default:
				elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
				break;
		}

		/* Print the relation alias, if needed */
		printalias = false;
		if (rte->alias != NULL)
		{
			/* Always print alias if user provided one */
			printalias = true;
		}
		else if (colinfo->printaliases)
		{
			/* Always print alias if we need to print column aliases */
			printalias = true;
		}
		else if (rte->rtekind == RTE_RELATION)
		{
			/*
			 * No need to print alias if it's same as relation name (this
			 * would normally be the case, but not if set_rtable_names had to
			 * resolve a conflict).
			 */
			if (strcmp(refname, get_relation_name(rte->relid)) != 0)
				printalias = true;
		}
		else if (rte->rtekind == RTE_FUNCTION)
		{
			/*
			 * For a function RTE, always print alias.  This covers possible
			 * renaming of the function and/or instability of the
			 * FigureColname rules for things that aren't simple functions.
			 * Note we'd need to force it anyway for the columndef list case.
			 */
			printalias = true;
		}
		else if (rte->rtekind == RTE_VALUES)
		{
			/* Alias is syntactically required for VALUES */
			printalias = true;
		}
		else if (rte->rtekind == RTE_CTE)
		{
			/*
			 * No need to print alias if it's same as CTE name (this would
			 * normally be the case, but not if set_rtable_names had to
			 * resolve a conflict).
			 */
			if (strcmp(refname, rte->ctename) != 0)
				printalias = true;
		}
		else if (rte->rtekind == RTE_SUBQUERY)
		{
			/* subquery requires alias too */
			printalias = true;
		}
		if (printalias)
			appendStringInfo(buf, " %s", quote_identifier(refname));

		/* Print the column definitions or aliases, if needed */
		if (rtfunc1 && rtfunc1->funccolnames != NIL)
		{
			/* Reconstruct the columndef list, which is also the aliases */
			get_from_clause_coldeflist(rtfunc1, colinfo, context);
		}
		else if (GetRangeTblKind(rte) != CITUS_RTE_SHARD ||
				 (rte->alias != NULL && rte->alias->colnames != NIL))
		{
			/* Else print column aliases as needed */
			get_column_alias_list(colinfo, context);
		}
		/* check if column's are given aliases in distributed tables */
		else if (colinfo->parentUsing != NIL)
		{
			Assert(colinfo->printaliases);
			get_column_alias_list(colinfo, context);
		}

		/* Tablesample clause must go after any alias */
		if ((rteKind == CITUS_RTE_RELATION || rteKind == CITUS_RTE_SHARD) &&
			rte->tablesample)
		{
			get_tablesample_def(rte->tablesample, context);
		}
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;
		deparse_columns *colinfo = deparse_columns_fetch(j->rtindex, dpns);
		bool		need_paren_on_right;

		need_paren_on_right = PRETTY_PAREN(context) &&
			!IsA(j->rarg, RangeTblRef) &&
			!(IsA(j->rarg, JoinExpr) && ((JoinExpr *) j->rarg)->alias != NULL);

		if (!PRETTY_PAREN(context) || j->alias != NULL)
			appendStringInfoChar(buf, '(');

		get_from_clause_item(j->larg, query, context);

		switch (j->jointype)
		{
			case JOIN_INNER:
				if (j->quals)
					appendContextKeyword(context, " JOIN ",
										 -PRETTYINDENT_STD,
										 PRETTYINDENT_STD,
										 PRETTYINDENT_JOIN);
				else
					appendContextKeyword(context, " CROSS JOIN ",
										 -PRETTYINDENT_STD,
										 PRETTYINDENT_STD,
										 PRETTYINDENT_JOIN);
				break;
			case JOIN_LEFT:
				appendContextKeyword(context, " LEFT JOIN ",
									 -PRETTYINDENT_STD,
									 PRETTYINDENT_STD,
									 PRETTYINDENT_JOIN);
				break;
			case JOIN_FULL:
				appendContextKeyword(context, " FULL JOIN ",
									 -PRETTYINDENT_STD,
									 PRETTYINDENT_STD,
									 PRETTYINDENT_JOIN);
				break;
			case JOIN_RIGHT:
				appendContextKeyword(context, " RIGHT JOIN ",
									 -PRETTYINDENT_STD,
									 PRETTYINDENT_STD,
									 PRETTYINDENT_JOIN);
				break;
			default:
				elog(ERROR, "unrecognized join type: %d",
					 (int) j->jointype);
		}

		if (need_paren_on_right)
			appendStringInfoChar(buf, '(');
		get_from_clause_item(j->rarg, query, context);
		if (need_paren_on_right)
			appendStringInfoChar(buf, ')');

		if (j->usingClause)
		{
			ListCell   *lc;
			bool		first = true;

			appendStringInfoString(buf, " USING (");
			/* Use the assigned names, not what's in usingClause */
			foreach(lc, colinfo->usingNames)
			{
				char	   *colname = (char *) lfirst(lc);

				if (first)
					first = false;
				else
					appendStringInfoString(buf, ", ");
				appendStringInfoString(buf, quote_identifier(colname));
			}
			appendStringInfoChar(buf, ')');

			if (j->join_using_alias)
				appendStringInfo(buf, " AS %s",
								 quote_identifier(j->join_using_alias->aliasname));
		}
		else if (j->quals)
		{
			appendStringInfoString(buf, " ON ");
			if (!PRETTY_PAREN(context))
				appendStringInfoChar(buf, '(');
			get_rule_expr(j->quals, context, false);
			if (!PRETTY_PAREN(context))
				appendStringInfoChar(buf, ')');
		}
		else if (j->jointype != JOIN_INNER)
		{
			/* If we didn't say CROSS JOIN above, we must provide an ON */
			appendStringInfoString(buf, " ON TRUE");
		}

		if (!PRETTY_PAREN(context) || j->alias != NULL)
			appendStringInfoChar(buf, ')');

		/* Yes, it's correct to put alias after the right paren ... */
		if (j->alias != NULL)
		{
			/*
			 * Note that it's correct to emit an alias clause if and only if
			 * there was one originally.  Otherwise we'd be converting a named
			 * join to unnamed or vice versa, which creates semantic
			 * subtleties we don't want.  However, we might print a different
			 * alias name than was there originally.
			 */
			appendStringInfo(buf, " %s",
							 quote_identifier(get_rtable_name(j->rtindex,
															  context)));
			get_column_alias_list(colinfo, context);
		}
	}
	else
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
}

/*
 * get_column_alias_list - print column alias list for an RTE
 *
 * Caller must already have printed the relation's alias name.
 */
static void
get_column_alias_list(deparse_columns *colinfo, deparse_context *context)
{
	StringInfo	buf = context->buf;
	int			i;
	bool		first = true;

	/* Don't print aliases if not needed */
	if (!colinfo->printaliases)
		return;

	for (i = 0; i < colinfo->num_new_cols; i++)
	{
		char	   *colname = colinfo->new_colnames[i];

		if (first)
		{
			appendStringInfoChar(buf, '(');
			first = false;
		}
		else
			appendStringInfoString(buf, ", ");
		appendStringInfoString(buf, quote_identifier(colname));
	}
	if (!first)
		appendStringInfoChar(buf, ')');
}

/*
 * get_from_clause_coldeflist - reproduce FROM clause coldeflist
 *
 * When printing a top-level coldeflist (which is syntactically also the
 * relation's column alias list), use column names from colinfo.  But when
 * printing a coldeflist embedded inside ROWS FROM(), we prefer to use the
 * original coldeflist's names, which are available in rtfunc->funccolnames.
 * Pass NULL for colinfo to select the latter behavior.
 *
 * The coldeflist is appended immediately (no space) to buf.  Caller is
 * responsible for ensuring that an alias or AS is present before it.
 */
static void
get_from_clause_coldeflist(RangeTblFunction *rtfunc,
						   deparse_columns *colinfo,
						   deparse_context *context)
{
	StringInfo	buf = context->buf;
	ListCell   *l1;
	ListCell   *l2;
	ListCell   *l3;
	ListCell   *l4;
	int			i;

	appendStringInfoChar(buf, '(');

	i = 0;
	forfour(l1, rtfunc->funccoltypes,
			l2, rtfunc->funccoltypmods,
			l3, rtfunc->funccolcollations,
			l4, rtfunc->funccolnames)
	{
		Oid			atttypid = lfirst_oid(l1);
		int32		atttypmod = lfirst_int(l2);
		Oid			attcollation = lfirst_oid(l3);
		char	   *attname;

		if (colinfo)
			attname = colinfo->colnames[i];
		else
			attname = strVal(lfirst(l4));

		Assert(attname);		/* shouldn't be any dropped columns here */

		if (i > 0)
			appendStringInfoString(buf, ", ");
		appendStringInfo(buf, "%s %s",
						 quote_identifier(attname),
						 format_type_with_typemod(atttypid, atttypmod));
		if (OidIsValid(attcollation) &&
			attcollation != get_typcollation(atttypid))
			appendStringInfo(buf, " COLLATE %s",
							 generate_collation_name(attcollation));

		i++;
	}

	appendStringInfoChar(buf, ')');
}

/*
 * get_tablesample_def			- print a TableSampleClause
 */
static void
get_tablesample_def(TableSampleClause *tablesample, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Oid			argtypes[1];
	int			nargs;
	ListCell   *l;

	/*
	 * We should qualify the handler's function name if it wouldn't be
	 * resolved by lookup in the current search path.
	 */
	argtypes[0] = INTERNALOID;
	appendStringInfo(buf, " TABLESAMPLE %s (",
					 generate_function_name(tablesample->tsmhandler, 1,
											NIL, argtypes,
											false, NULL, EXPR_KIND_NONE));

	nargs = 0;
	foreach(l, tablesample->args)
	{
		if (nargs++ > 0)
			appendStringInfoString(buf, ", ");
		get_rule_expr((Node *) lfirst(l), context, false);
	}
	appendStringInfoChar(buf, ')');

	if (tablesample->repeatable != NULL)
	{
		appendStringInfoString(buf, " REPEATABLE (");
		get_rule_expr((Node *) tablesample->repeatable, context, false);
		appendStringInfoChar(buf, ')');
	}
}

/*
 * get_opclass_name			- fetch name of an index operator class
 *
 * The opclass name is appended (after a space) to buf.
 *
 * Output is suppressed if the opclass is the default for the given
 * actual_datatype.  (If you don't want this behavior, just pass
 * InvalidOid for actual_datatype.)
 */
static void
get_opclass_name(Oid opclass, Oid actual_datatype,
				 StringInfo buf)
{
	HeapTuple	ht_opc;
	Form_pg_opclass opcrec;
	char	   *opcname;
	char	   *nspname;

	ht_opc = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
	if (!HeapTupleIsValid(ht_opc))
		elog(ERROR, "cache lookup failed for opclass %u", opclass);
	opcrec = (Form_pg_opclass) GETSTRUCT(ht_opc);

	if (!OidIsValid(actual_datatype) ||
		GetDefaultOpClass(actual_datatype, opcrec->opcmethod) != opclass)
	{
		/* Okay, we need the opclass name.  Do we need to qualify it? */
		opcname = NameStr(opcrec->opcname);
		if (OpclassIsVisible(opclass))
			appendStringInfo(buf, " %s", quote_identifier(opcname));
		else
		{
			nspname = get_namespace_name_or_temp(opcrec->opcnamespace);
			appendStringInfo(buf, " %s.%s",
							 quote_identifier(nspname),
							 quote_identifier(opcname));
		}
	}
	ReleaseSysCache(ht_opc);
}

/*
 * processIndirection - take care of array and subfield assignment
 *
 * We strip any top-level FieldStore or assignment SubscriptingRef nodes that
 * appear in the input, printing them as decoration for the base column
 * name (which we assume the caller just printed).  We might also need to
 * strip CoerceToDomain nodes, but only ones that appear above assignment
 * nodes.
 *
 * Returns the subexpression that's to be assigned.
 */
static Node *
processIndirection(Node *node, deparse_context *context)
{
	StringInfo	buf = context->buf;
	CoerceToDomain *cdomain = NULL;

	for (;;)
	{
		if (node == NULL)
			break;
		if (IsA(node, FieldStore))
		{
			FieldStore *fstore = (FieldStore *) node;
			Oid			typrelid;
			char	   *fieldname;

			/* lookup tuple type */
			typrelid = get_typ_typrelid(fstore->resulttype);
			if (!OidIsValid(typrelid))
				elog(ERROR, "argument type %s of FieldStore is not a tuple type",
					 format_type_be(fstore->resulttype));

			/*
			 * Print the field name.  There should only be one target field in
			 * stored rules.  There could be more than that in executable
			 * target lists, but this function cannot be used for that case.
			 */
			Assert(list_length(fstore->fieldnums) == 1);
			fieldname = get_attname(typrelid,
									linitial_int(fstore->fieldnums), false);
			appendStringInfo(buf, ".%s", quote_identifier(fieldname));

			/*
			 * We ignore arg since it should be an uninteresting reference to
			 * the target column or subcolumn.
			 */
			node = (Node *) linitial(fstore->newvals);
		}
		else if (IsA(node, SubscriptingRef))
		{
			SubscriptingRef   *sbsref = (SubscriptingRef *) node;

			if (sbsref->refassgnexpr == NULL)
				break;
			printSubscripts(sbsref, context);

			/*
			 * We ignore refexpr since it should be an uninteresting reference
			 * to the target column or subcolumn.
			 */
			node = (Node *) sbsref->refassgnexpr;
		}
		else if (IsA(node, CoerceToDomain))
		{
			cdomain = (CoerceToDomain *) node;
			/* If it's an explicit domain coercion, we're done */
			if (cdomain->coercionformat != COERCE_IMPLICIT_CAST)
				break;
			/* Tentatively descend past the CoerceToDomain */
			node = (Node *) cdomain->arg;
		}
		else
			break;
	}

	/*
	 * If we descended past a CoerceToDomain whose argument turned out not to
	 * be a FieldStore or array assignment, back up to the CoerceToDomain.
	 * (This is not enough to be fully correct if there are nested implicit
	 * CoerceToDomains, but such cases shouldn't ever occur.)
	 */
	if (cdomain && node == (Node *) cdomain->arg)
		node = (Node *) cdomain;

	return node;
}

static void
printSubscripts(SubscriptingRef *sbsref, deparse_context *context)
{
	StringInfo	buf = context->buf;
	ListCell   *lowlist_item;
	ListCell   *uplist_item;

	lowlist_item = list_head(sbsref->reflowerindexpr);	/* could be NULL */
	foreach(uplist_item, sbsref->refupperindexpr)
	{
		appendStringInfoChar(buf, '[');
		if (lowlist_item)
		{
			/* If subexpression is NULL, get_rule_expr prints nothing */
			get_rule_expr((Node *) lfirst(lowlist_item), context, false);
			appendStringInfoChar(buf, ':');
			lowlist_item = lnext(sbsref->reflowerindexpr, lowlist_item);
		}
		/* If subexpression is NULL, get_rule_expr prints nothing */
		get_rule_expr((Node *) lfirst(uplist_item), context, false);
		appendStringInfoChar(buf, ']');
	}
}

/*
 * get_relation_name
 *		Get the unqualified name of a relation specified by OID
 *
 * This differs from the underlying get_rel_name() function in that it will
 * throw error instead of silently returning NULL if the OID is bad.
 */
static char *
get_relation_name(Oid relid)
{
	char	   *relname = get_rel_name(relid);

	if (!relname)
		elog(ERROR, "cache lookup failed for relation %u", relid);
	return relname;
}

/*
 * generate_relation_or_shard_name
 *		Compute the name to display for a relation or shard
 *
 * If the provided relid is equal to the provided distrelid, this function
 * returns a shard-extended relation name; otherwise, it falls through to a
 * simple generate_relation_name call.
 */
static char *
generate_relation_or_shard_name(Oid relid, Oid distrelid, int64 shardid,
								List *namespaces)
{
	char *relname = NULL;

	if (relid == distrelid)
	{
		relname = get_relation_name(relid);

		if (shardid > 0)
		{
			Oid schemaOid = get_rel_namespace(relid);
			char *schemaName = get_namespace_name_or_temp(schemaOid);

			AppendShardIdToName(&relname, shardid);

			relname = quote_qualified_identifier(schemaName, relname);
		}
	}
	else
	{
		relname = generate_relation_name(relid, namespaces);
	}

	return relname;
}

/*
 * generate_relation_name
 *		Compute the name to display for a relation specified by OID
 *
 * The result includes all necessary quoting and schema-prefixing.
 *
 * If namespaces isn't NIL, it must be a list of deparse_namespace nodes.
 * We will forcibly qualify the relation name if it equals any CTE name
 * visible in the namespace list.
 */
char *
generate_relation_name(Oid relid, List *namespaces)
{
	HeapTuple	tp;
	Form_pg_class reltup;
	bool		need_qual;
	ListCell   *nslist;
	char	   *relname;
	char	   *nspname;
	char	   *result;

	tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for relation %u", relid);
	reltup = (Form_pg_class) GETSTRUCT(tp);
	relname = NameStr(reltup->relname);

	/* Check for conflicting CTE name */
	need_qual = false;
	foreach(nslist, namespaces)
	{
		deparse_namespace *dpns = (deparse_namespace *) lfirst(nslist);
		ListCell   *ctlist;

		foreach(ctlist, dpns->ctes)
		{
			CommonTableExpr *cte = (CommonTableExpr *) lfirst(ctlist);

			if (strcmp(cte->ctename, relname) == 0)
			{
				need_qual = true;
				break;
			}
		}
		if (need_qual)
			break;
	}

	/* Otherwise, qualify the name if not visible in search path */
	if (!need_qual)
		need_qual = !RelationIsVisible(relid);

	if (need_qual)
		nspname = get_namespace_name_or_temp(reltup->relnamespace);
	else
		nspname = NULL;

	result = quote_qualified_identifier(nspname, relname);

	ReleaseSysCache(tp);

	return result;
}

/*
 * generate_rte_shard_name returns the qualified name of the shard given a
 * CITUS_RTE_SHARD range table entry.
 */
static char *
generate_rte_shard_name(RangeTblEntry *rangeTableEntry)
{
	char *shardSchemaName = NULL;
	char *shardTableName = NULL;

	Assert(GetRangeTblKind(rangeTableEntry) == CITUS_RTE_SHARD);

	ExtractRangeTblExtraData(rangeTableEntry, NULL, &shardSchemaName, &shardTableName,
							 NULL);

	return generate_fragment_name(shardSchemaName, shardTableName);
}

/*
 * generate_fragment_name
 *		Compute the name to display for a shard or merged table
 *
 * The result includes all necessary quoting and schema-prefixing. The schema
 * name can be NULL for regular shards. For merged tables, they are always
 * declared within a job-specific schema, and therefore can't have null schema
 * names.
 */
static char *
generate_fragment_name(char *schemaName, char *tableName)
{
	StringInfo fragmentNameString = makeStringInfo();

	if (schemaName != NULL)
	{
		appendStringInfo(fragmentNameString, "%s.%s", quote_identifier(schemaName),
						 quote_identifier(tableName));
	}
	else
	{
		appendStringInfoString(fragmentNameString, quote_identifier(tableName));
	}

	return fragmentNameString->data;
}

/*
 * generate_function_name
 *		Compute the name to display for a function specified by OID,
 *		given that it is being called with the specified actual arg names and
 *		types.  (Those matter because of ambiguous-function resolution rules.)
 *
 * If we're dealing with a potentially variadic function (in practice, this
 * means a FuncExpr or Aggref, not some other way of calling a function), then
 * has_variadic must specify whether variadic arguments have been merged,
 * and *use_variadic_p will be set to indicate whether to print VARIADIC in
 * the output.  For non-FuncExpr cases, has_variadic should be false and
 * use_variadic_p can be NULL.
 *
 * The result includes all necessary quoting and schema-prefixing.
 */
static char *
generate_function_name(Oid funcid, int nargs, List *argnames, Oid *argtypes,
					   bool has_variadic, bool *use_variadic_p,
					   ParseExprKind special_exprkind)
{
	char	   *result;
	HeapTuple	proctup;
	Form_pg_proc procform;
	char	   *proname;
	bool		use_variadic;
	char	   *nspname;
	FuncDetailCode p_result;
	Oid			p_funcid;
	Oid			p_rettype;
	bool		p_retset;
	int			p_nvargs;
	Oid			p_vatype;
	Oid		   *p_true_typeids;
	bool		force_qualify = false;

	proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
	if (!HeapTupleIsValid(proctup))
		elog(ERROR, "cache lookup failed for function %u", funcid);
	procform = (Form_pg_proc) GETSTRUCT(proctup);
	proname = NameStr(procform->proname);

	/*
	 * Due to parser hacks to avoid needing to reserve CUBE, we need to force
	 * qualification in some special cases.
	 */
	if (special_exprkind == EXPR_KIND_GROUP_BY)
	{
		if (strcmp(proname, "cube") == 0 || strcmp(proname, "rollup") == 0)
			force_qualify = true;
	}

	/*
	 * Determine whether VARIADIC should be printed.  We must do this first
	 * since it affects the lookup rules in func_get_detail().
	 *
	 * Currently, we always print VARIADIC if the function has a merged
	 * variadic-array argument.  Note that this is always the case for
	 * functions taking a VARIADIC argument type other than VARIADIC ANY.
	 *
	 * In principle, if VARIADIC wasn't originally specified and the array
	 * actual argument is deconstructable, we could print the array elements
	 * separately and not print VARIADIC, thus more nearly reproducing the
	 * original input.  For the moment that seems like too much complication
	 * for the benefit, and anyway we do not know whether VARIADIC was
	 * originally specified if it's a non-ANY type.
	 */
	if (use_variadic_p)
	{
		/* Parser should not have set funcvariadic unless fn is variadic */
		Assert(!has_variadic || OidIsValid(procform->provariadic));
		use_variadic = has_variadic;
		*use_variadic_p = use_variadic;
	}
	else
	{
		Assert(!has_variadic);
		use_variadic = false;
	}

	/*
	 * The idea here is to schema-qualify only if the parser would fail to
	 * resolve the correct function given the unqualified func name with the
	 * specified argtypes and VARIADIC flag.  But if we already decided to
	 * force qualification, then we can skip the lookup and pretend we didn't
	 * find it.
	 */
	if (!force_qualify)
		p_result = func_get_detail(list_make1(makeString(proname)),
								   NIL, argnames, nargs, argtypes,
								   !use_variadic, true, false,
								   &p_funcid, &p_rettype,
								   &p_retset, &p_nvargs, &p_vatype,
								   &p_true_typeids, NULL);
	else
	{
		p_result = FUNCDETAIL_NOTFOUND;
		p_funcid = InvalidOid;
	}

	if ((p_result == FUNCDETAIL_NORMAL ||
		 p_result == FUNCDETAIL_AGGREGATE ||
		 p_result == FUNCDETAIL_WINDOWFUNC) &&
		p_funcid == funcid)
		nspname = NULL;
	else
		nspname = get_namespace_name_or_temp(procform->pronamespace);

	result = quote_qualified_identifier(nspname, proname);

	ReleaseSysCache(proctup);

	return result;
}

/*
 * generate_operator_name
 *		Compute the name to display for an operator specified by OID,
 *		given that it is being called with the specified actual arg types.
 *		(Arg types matter because of ambiguous-operator resolution rules.
 *		Pass InvalidOid for unused arg of a unary operator.)
 *
 * The result includes all necessary quoting and schema-prefixing,
 * plus the OPERATOR() decoration needed to use a qualified operator name
 * in an expression.
 */
char *
generate_operator_name(Oid operid, Oid arg1, Oid arg2)
{
	StringInfoData buf;
	HeapTuple	opertup;
	Form_pg_operator operform;
	char	   *oprname;
	char	   *nspname;

	initStringInfo(&buf);

	opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(operid));
	if (!HeapTupleIsValid(opertup))
		elog(ERROR, "cache lookup failed for operator %u", operid);
	operform = (Form_pg_operator) GETSTRUCT(opertup);
	oprname = NameStr(operform->oprname);

	/*
	 * Unlike generate_operator_name() in postgres/src/backend/utils/adt/ruleutils.c,
	 * we don't check if the operator is in current namespace or not. This is
	 * because this check is costly when the operator is not in current namespace.
	 */
	nspname = get_namespace_name_or_temp(operform->oprnamespace);
	Assert(nspname != NULL);
	appendStringInfo(&buf, "OPERATOR(%s.", quote_identifier(nspname));
	appendStringInfoString(&buf, oprname);
	appendStringInfoChar(&buf, ')');

	ReleaseSysCache(opertup);

	return buf.data;
}

/*
 * get_one_range_partition_bound_string
 *		A C string representation of one range partition bound
 */
char *
get_range_partbound_string(List *bound_datums)
{
	deparse_context context;
	StringInfo	buf = makeStringInfo();
	ListCell   *cell;
	char	   *sep;

	memset(&context, 0, sizeof(deparse_context));
	context.buf = buf;

	appendStringInfoChar(buf, '(');
	sep = "";
	foreach(cell, bound_datums)
	{
		PartitionRangeDatum *datum =
		lfirst_node(PartitionRangeDatum, cell);

		appendStringInfoString(buf, sep);
		if (datum->kind == PARTITION_RANGE_DATUM_MINVALUE)
			appendStringInfoString(buf, "MINVALUE");
		else if (datum->kind == PARTITION_RANGE_DATUM_MAXVALUE)
			appendStringInfoString(buf, "MAXVALUE");
		else
		{
			Const	   *val = castNode(Const, datum->value);

			get_const_expr(val, &context, -1);
		}
		sep = ", ";
	}
	appendStringInfoChar(buf, ')');

	return buf->data;
}

/*
 * Collect a list of OIDs of all sequences owned by the specified relation,
 * and column if specified.  If deptype is not zero, then only find sequences
 * with the specified dependency type.
 */
List *
getOwnedSequences_internal(Oid relid, AttrNumber attnum, char deptype)
{
	List	   *result = NIL;
	Relation	depRel;
	ScanKeyData key[3];
	SysScanDesc scan;
	HeapTuple	tup;

	depRel = table_open(DependRelationId, AccessShareLock);

	ScanKeyInit(&key[0],
				Anum_pg_depend_refclassid,
				BTEqualStrategyNumber, F_OIDEQ,
				ObjectIdGetDatum(RelationRelationId));
	ScanKeyInit(&key[1],
				Anum_pg_depend_refobjid,
				BTEqualStrategyNumber, F_OIDEQ,
				ObjectIdGetDatum(relid));
	if (attnum)
		ScanKeyInit(&key[2],
					Anum_pg_depend_refobjsubid,
					BTEqualStrategyNumber, F_INT4EQ,
					Int32GetDatum(attnum));

	scan = systable_beginscan(depRel, DependReferenceIndexId, true,
							  NULL, attnum ? 3 : 2, key);

	while (HeapTupleIsValid(tup = systable_getnext(scan)))
	{
		Form_pg_depend deprec = (Form_pg_depend) GETSTRUCT(tup);

		/*
		 * We assume any auto or internal dependency of a sequence on a column
		 * must be what we are looking for.  (We need the relkind test because
		 * indexes can also have auto dependencies on columns.)
		 */
		if (deprec->classid == RelationRelationId &&
			deprec->objsubid == 0 &&
			deprec->refobjsubid != 0 &&
			(deprec->deptype == DEPENDENCY_AUTO || deprec->deptype == DEPENDENCY_INTERNAL) &&
			get_rel_relkind(deprec->objid) == RELKIND_SEQUENCE)
		{
			if (!deptype || deprec->deptype == deptype)
				result = lappend_oid(result, deprec->objid);
		}
	}

	systable_endscan(scan);

	table_close(depRel, AccessShareLock);

	return result;
}

/*
 * get_insert_column_names_list Prepares the insert-column-names list. Any indirection
 * decoration needed on the column names can be inferred from the top targetlist.
 */
static List *
get_insert_column_names_list(List *targetList, StringInfo buf,
					deparse_context *context, RangeTblEntry *rte)
{
	char *sep;
	ListCell *l;
	List *strippedexprs;

	strippedexprs = NIL;
	sep = "";
	appendStringInfoChar(buf, '(');
	foreach(l, targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);

		if (tle->resjunk)
			continue;			/* ignore junk entries */

		appendStringInfoString(buf, sep);
		sep = ", ";

		/*
		 * Put out name of target column; look in the catalogs, not at
		 * tle->resname, since resname will fail to track RENAME.
		 */
		appendStringInfoString(buf,
							   quote_identifier(get_attname(rte->relid,
															tle->resno,
															false)));

		/*
		 * Print any indirection needed (subfields or subscripts), and strip
		 * off the top-level nodes representing the indirection assignments.
		 * Add the stripped expressions to strippedexprs.  (If it's a
		 * single-VALUES statement, the stripped expressions are the VALUES to
		 * print below.  Otherwise they're just Vars and not really
		 * interesting.)
		 */
		strippedexprs = lappend(strippedexprs,
								processIndirection((Node *) tle->expr,
												   context));
	}
	appendStringInfoString(buf, ") ");

	return strippedexprs;
}
#endif /* (PG_VERSION_NUM >= PG_VERSION_15) && (PG_VERSION_NUM < PG_VERSION_16) */
