---

Features

• Cloning table columns
• Cloning table indexes
• Cloning table data
• Cloning table collation

Why not use a default built-in replication methods

The default replication has some weak points:

• It creates a big binlog file (if you have a big database) - so you need a large amount of disk space to handle those binlogs
• It does not supports the triggers - triggers will be saved as SQL-query in binlog, but if you want to have a copy of just a few tables - some data will be incorrect.

How to setup

First of all you'll need a Composer

If you don't have it yet installed, - checkout this guide.

Then add the library to your project

composer require yerofey/replicator

If you want to replicate on the same server:

1. You can create a worker that will do the job for example every minute (examples/worker.php) It can be setted up with crontab.
2. You can create a daemon that will work always and do the job every n seconds (examples/daemon.php)

If you want to replicate on another server:

On secondary server (Linux):

sudo nano /etc/mysql/mysql.conf.d/mysqld.cnf

Navigate to the line that begins with the bind-address directive. By default, this value is set to 127.0.0.1, meaning that the server will only look for local connections. You will need to change this directive to reference an external IP address. For the purposes of troubleshooting, you could set this directive to a wildcard IP address, either *, ::, or 0.0.0.0:

bind-address            = 0.0.0.0

After changing this line, save and close the file (CTRL + X, Y, then ENTER if you edited it with nano).

Assuming you’ve configured a firewall on your database server, you will also need to open port 3306 — MySQL’s default port — to allow traffic to MySQL. If you only plan to access the database server from one specific machine, you can grant that machine exclusive permission to connect to the database remotely with the following command. Make sure to replace remote_IP_address with the actual IP address of the machine you plan to connect with:

sudo ufw allow from REMOTE_IP_ADDRESS to any port 3306

Alternatively, you can allow connections to your MySQL database from any IP address with the following command:

sudo ufw allow 3306

Lastly, restart the MySQL service to put the changes you made to mysqld.cnf into effect:

sudo systemctl restart mysql

MySQL setup guide source: https://www.digitalocean.com/community/tutorials/how-to-allow-remote-access-to-mysql

Then create a folder for a worker scripts

mkdir db-replicator
cd db-replicator

Then create a DB configuration file

touch config.php

config.php example

<?php

require __DIR__ . '/vendor/autoload.php';

// load variables from ".env" file
$dotenv = Dotenv\Dotenv::createImmutable(__DIR__);
$dotenv->load();

if (!isset($_ENV['DB_REPLICATION_IS_ENABLED']) || $_ENV['DB_REPLICATION_IS_ENABLED'] == false) {
  exit();
}

$config_db_map = [
  'primary' => [
    'hostname' => $_ENV['DB_PRIMARY_HOST'],
    'database' => $_ENV['DB_PRIMARY_NAME'],
    'username' => $_ENV['DB_PRIMARY_USER'],
    'password' => $_ENV['DB_PRIMARY_PASS'],
  ],
  'secondary' => [
    'hostname' => $_ENV['DB_SECONDARY_HOST'],
    'database' => $_ENV['DB_SECONDARY_NAME'],
    'username' => $_ENV['DB_SECONDARY_USER'],
    'password' => $_ENV['DB_SECONDARY_PASS'],
  ],
];

Then create a worker script (one time job)

<?php

// one-time worker replication script

ini_set('memory_limit', '256M');
set_time_limit(300);

// your app root location
$app_dir = __DIR__ . '/..';

// log actions in "/replicator_log.txt"
$debug = true;
$log_file = $app_dir . '/replicator_log.txt';

// master table config key from "config.php"
$primary_db_key = 'primary';
// slave table config key from "config.php"
$secondary_db_key = 'secondary';

// specifed tables to watch OR use "*" to watch for all tables
$watch_tables = [
  'test_table',
];

// load Composer
require $app_dir . '/vendor/autoload.php';
// load DB config map
require __DIR__ . '/config.php';

use Yerofey\Replicator\Replicator;
use Yerofey\Replicator\ReplicatorException;
use Yerofey\Replicator\ReplicatorHelper;

if (!isset($config_db_map)) {
  exit();
}

// init helper
$helper = new ReplicatorHelper();

// init DB connections
try {
  $connections = [
    'primary'   => $helper->createConnection($config_db_map[$primary_db_key] ?? []),
    'secondary' => $helper->createConnection($config_db_map[$secondary_db_key] ?? []),
  ];
} catch (ReplicatorException $e) {
  exit($e->getMessage() . PHP_EOL);
}

// init Replicator
$replicator = new Replicator(
  $connections,
  $helper,
  $debug,
  $log_file
);

// run Replicator
try {
  $replicator->run($watch_tables);
} catch (ReplicatorException $e) {
  $replicator->saveLog($e->getMessage());
}

Or create a daemon (that will work always)

<?php

// daemon worker replication script

ini_set('memory_limit', '256M');
set_time_limit(0);

// your app root location
$app_dir = __DIR__ . '/..';

// log actions in "/replicator_log.txt"
$debug = true;
$log_file = $app_dir . '/replicator_log.txt';

// master table config key from "config.php"
$primary_db_key = 'primary';
// slave table config key from "config.php"
$secondary_db_key = 'secondary';

// specifed tables to watch OR use "*" to watch for all tables
$watch_tables = [
  'test_table',
];

// watch interval (sec)
$interval_seconds = 10;

// load Composer
require $app_dir . '/vendor/autoload.php';
// load DB config map
require __DIR__ . '/config.php';

use Yerofey\Replicator\Replicator;
use Yerofey\Replicator\ReplicatorException;
use Yerofey\Replicator\ReplicatorHelper;

if (!isset($config_db_map)) {
  exit();
}

// init helper
$helper = new ReplicatorHelper();

// init DB connections
try {
  $connections = [
    'primary'   => $helper->createConnection($config_db_map[$primary_db_key] ?? []),
    'secondary' => $helper->createConnection($config_db_map[$secondary_db_key] ?? []),
  ];
} catch (ReplicatorException $e) {
  exit($e->getMessage() . PHP_EOL);
}

// init Replicator
$replicator = new Replicator(
  $connections,
  $helper,
  $debug,
  $log_file
);

// run Replicator
while (true) {
  $time_start = microtime(true);

  try {
    $replicator->run($watch_tables);
  } catch (ReplicatorException $e) {
    $replicator->saveLog($e->getMessage());
  }

  $sleep = 0;
  $runtime = microtime(true) - $time_start;
  if ($runtime < $interval_seconds) {
    $sleep = $interval_seconds - $runtime;
  }

  sleep($sleep);
}

Then just run your script

If you've done everything right replication should now work.

Author

Yerofey S.

License

This library licensed under MIT.