How to customize WordPress for MySQL replication

Step 1: Configure the Master Database

1. Set the Master Database Host:
- In `wp-config.php`, set `DB_HOST` to the IP address of your master MySQL server.

php
   define('DB_HOST', 'master_server_IP');
   

Step 2: Configure the Slave Database

1. Set the Slave Database Host:
- In `wp-config.php`, set `DB_SLAVE_1` to the IP address of your slave MySQL server.

php
   define('DB_SLAVE_1', 'slave_server_IP');
   

Step 3: Configure Read and Write Options

1. Set Read Options:
- In `wp-config.php`, set `read` to `1` for the slave database to ensure WordPress reads from the slave.

php
   $wpdb->add_database(array(
       'host' => DB_SLAVE_1,
       'user' => DB_USER,
       'password' => DB_PASSWORD,
       'name' => DB_NAME,
       'write' => 0,
       'read' => 1,
       'dataset' => 'global',
       'timeout' => 0.2,
   ));
   

Step 4: Configure HyperDB (Optional)

1. Install HyperDB:
- Download and install the HyperDB plugin for WordPress.

2. Configure HyperDB:
- Configure HyperDB to use the master and slave databases. This will allow WordPress to write to the master and read from the slave.

Step 5: Restart WordPress

1. Restart WordPress:
- Restart your WordPress application to apply the new configuration.

By following these steps, you can configure WordPress to use MySQL replication effectively, ensuring that writes are handled by the master database and reads are handled by the slave database.