[![CircleCI](https://circleci.com/gh/mydumper/mydumper/tree/master.svg?style=svg)](https://circleci.com/gh/mydumper/mydumper/tree/master)

 # What is MyDumper?
MyDumper is a MySQL Logical Backup Tool. It has 2 tools:
* `mydumper` which is responsible to export a consistent backup of MySQL databases
* `myloader` reads the backup from mydumper, connects the to destination database and imports the backup.

Both tools use multithreading capabilities.
<br>MyDumper is Open Source and maintained by the community, it is not a Percona, MariaDB or MySQL product.

# Why do we need MyDumper?
* Parallelism (hence, speed) and performance (avoids expensive character set conversion routines, efficient code overall)
* Easier to manage output (separate files for tables, dump metadata, etc, easy to view/parse data)
* Consistency - maintains snapshot across all threads, provides accurate master and slave log positions, etc
* Manageability - supports PCRE for specifying database and tables inclusions and exclusions

## How to install mydumper/myloader?

First get the correct url from the [releases section](https://github.com/maxbube/mydumper/releases) then:

### RedHat / Centos

```bash
release=$(curl -Ls -o /dev/null -w %{url_effective} https://github.com/mydumper/mydumper/releases/latest | cut -d'/' -f8)
yum install https://github.com/mydumper/mydumper/releases/download/${release}/mydumper-${release:1}.el7.x86_64.rpm
yum install https://github.com/mydumper/mydumper/releases/download/${release}/mydumper-${release:1}.el8.x86_64.rpm
```

### Ubuntu / Debian
For ubuntu, you need to install the dependencies:
```bash
apt-get install libatomic1
```
Then you can download and install the package:
```bash
release=$(curl -Ls -o /dev/null -w %{url_effective} https://github.com/mydumper/mydumper/releases/latest | cut -d'/' -f8)
wget https://github.com/mydumper/mydumper/releases/download/${release}/mydumper_${release:1}.$(lsb_release -cs)_amd64.deb
dpkg -i mydumper_${release:1}.$(lsb_release -cs)_amd64.deb
```

### FreeBSD
By using pkg

```bash
pkg install mydumper
```
or from ports

```bash
cd /usr/ports/databases/mydumper && make install
```

### MacOS
By using [Homebrew](https://brew.sh/)

```bash
brew install mydumper
```
Take into account that the mydumper.cnf file is going to be located on /usr/local/etc or /opt/homebrew/etc.
So, you might need to run mydumper/myloader with:
```bash
mydumper --defaults-file=/opt/homebrew/etc/mydumper.cnf
myloader --defaults-file=/opt/homebrew/etc/mydumper.cnf
```

## Dependencies for building MyDumper

### Install development tools:
* Ubuntu or Debian:
```shell
apt-get install cmake g++ git
```
* Fedora, RedHat and CentOS:
```shell
yum install -y cmake gcc gcc-c++ git make
```
* MacOS <= 10.13 (High Sierra) < 13 (Ventura) with MacPorts package manager:

```shell
sudo port install cmake pkgconfig
```
### Install development versions of GLib, ZLib, PCRE and ZSTD:
* Ubuntu or Debian:
```shell
apt-get install libglib2.0-dev zlib1g-dev libpcre3-dev libssl-dev libzstd-dev
```
* Fedora, RedHat and CentOS:
```shell
yum install -y glib2-devel openssl-devel pcre-devel zlib-devel libzstd-devel
```
* openSUSE:
```shell
zypper install glib2-devel libmysqlclient-devel pcre-devel zlib-devel
```
* MacOS <= 10.13 (High Sierra) < 13 (Ventura) with MacPorts package manager:
```shell
sudo port install glib2 pcre
```
### Install MySQL/Percona/MariaDB development versions:
You need to select one vendor development library.
* Ubuntu or Debian:
```shell
apt-get install libmysqlclient-dev
apt-get install libperconaserverclient20-dev
apt-get install libmariadbclient-dev
```
* Fedora, RedHat and CentOS:
```shell
yum install -y mysql-devel
yum install -y Percona-Server-devel-57
yum install -y mariadb-devel
```
CentOS 7 comes by default with MariaDB 5.5 libraries which are very old.
  It might be better to download a newer version of these libraries (MariaDB, MySQL, Percona etc).
* openSUSE:
```shell
zypper install libmysqlclient-devel
```

* MacOS <= 10.13 (High Sierra) < 13 (Ventura) with MacPorts package manager
``` shell
sudo port install mariadb-10.11
sudo port select mysql
```
## How to Build

Run:

```shell
cmake .
make
sudo make install
```

One has to make sure, that pkg-config, mysql_config, pcre-config are all in $PATH

Binlog dump is disabled by default to compile with it you need to add -DWITH_BINLOG=ON to cmake options

To build against mysql libs < 5.7 you need to disable SSL adding -DWITH_SSL=OFF

### Build Docker image
You can download the [official docker image](https://hub.docker.com/r/mydumper/mydumper) or you can build the Docker image either from local sources or directly from Github sources with [the provided Dockerfile](./Dockerfile).
```shell
docker build --build-arg CMAKE_ARGS='-DWITH_ZSTD=ON' -t mydumper github.com/mydumper/mydumper
```
Keep in mind that the main purpose the Dockerfile addresses is development and build from source locally. It might not be optimal for distribution purposes, but can also work as a quick build and run solution with the above one-liner, though.

# How to use MyDumper

See [Usage](docs/mydumper_usage.rst)

## How does consistent snapshot work?

This is all done following best MySQL practices and traditions:

* As a precaution, slow running queries on the server either abort the dump, or get killed
* Global read lock is acquired ("FLUSH TABLES WITH READ LOCK")
* Various metadata is read ("SHOW SLAVE STATUS","SHOW MASTER STATUS")
* Other threads connect and establish snapshots ("START TRANSACTION WITH CONSISTENT SNAPSHOT")
** On pre-4.1.8 it creates dummy InnoDB table, and reads from it.
* Once all worker threads announce the snapshot establishment, master executes "UNLOCK TABLES" and starts queueing jobs.

This for now does not provide consistent snapshots for non-transactional engines - support for that is expected in 0.2 :)

## How to exclude (or include) databases?

Once can use --regex functionality, for example not to dump mysql and test databases:

```bash
 mydumper --regex '^(?!(mysql\.|test\.))'
```

To dump only mysql and test databases:

```bash
 mydumper --regex '^(mysql\.|test\.)'
```

To not dump all databases starting with test:

```bash
 mydumper --regex '^(?!(test))'
```

To dump specify tables in different databases (Note: The name of tables should end with $. [related issue](https://github.com/maxbube/mydumper/issues/407)):

```bash
 mydumper --regex '^(db1\.table1$|db2\.table2$)'
```

If you want to dump a couple of databases but discard some tables, you can do:
```bash
 mydumper --regex '^(?=(?:(db1\.|db2\.)))(?!(?:(db1\.table1$|db2\.table2$)))'
```
Which will dump all the tables in db1 and db2 but it will exclude db1.table1 and db2.table2

Of course, regex functionality can be used to describe pretty much any list of tables.


## How to use --exec?

You can execute external commands with --exec like this:

```bash
 mydumper --exec "/usr/bin/gzip FILENAME"
```

--exec is single threaded, similar implementation than Stream. The exec program must be an absolute path. FILENAME will be replaced by the filename that you want to be processed. You can set FILENAME in any place as argument.

## Defaults file

The default file (aka: --defaults-file parameter) is starting to be more important in MyDumper
- mydumper and myloader sections:

```bash
[mydumper]
host = 127.0.0.1
user = root
password = p455w0rd
database = db
rows = 10000

[myloader]
host = 127.0.0.1
user = root
password = p455w0rd
database = new_db
innodb-optimize-keys = AFTER_IMPORT_PER_TABLE
```

- Variables for mydumper and myloader executions:

Prior to v0.14.0-1:
```bash
[mydumper_variables]
wait_timeout = 300
sql_mode = ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION

[myloader_variables]
long_query_time = 300
innodb_flush_log_at_trx_commit = 0
```
From to v0.14.0-1:
```bash
[mydumper_session_variables]
wait_timeout = 300
sql_mode = ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION

[mydumper_global_variables]
sync_binlog = 0
slow_query_log = OFF

[myloader_session_variables]
long_query_time = 300

[myloader_global_variables]
sync_binlog = 0
innodb_flush_log_at_trx_commit = 0
```

- Per table sections:
```bash
[`db`.`table`]
where = column > 20
limit = 10000

[`myd_test`.`t`]
columns_on_select=qty,price+20
columns_on_insert=qty,price
```

IMPORTANT: when using options that doesn't required an argument like: --no-data or --events, you need to set any value to those variables which will always indicate: TRUE/ON/ENABLE. It is a MISCONCEPTION if you think that adding `--no-data=0` will export data:
```
[mydumper]
no-data=0
```
Will NOT export the data as no-data is being specified.
