How to set up HyperDB for WordPress website? - database

Question

I have a large database which I want to split into several databases but connected to my WordPress site. I searched through internet and came to a solution of using HyperDB class which is provided by WordPress Codex. I downloaded the files and I tried like below
$wpdb->add_database(array(
'host' => 'localhost', // If port is other than 3306, use host:port.
'user' => 'root',
'password' => '',
'name' => 'partitioning',
));
/**
* This adds the same server again, only this time it is configured as a slave.
* The last three parameters are set to the defaults but are shown for clarity.
*/
$wpdb->add_database(array(
'host' => 'localhost', // If port is other than 3306, use host:port.
'user' => 'root',
'password' => '',
'name' => 'slave',
'write' => 0,
'read' => 1,
'dataset' => 'global',
'timeout' => 0.2,
));
I am using xampp for the development version. After WordPress site installation I put the db-config.php along with wp-config.php file directory and db.php in wp-content folder. Doing this I get the blank page.
Can any one elaborate the process step by step how to set up the database and HyperDB scripts? I mean how to make the slave database or HyperDB will automatically make the slave database? How can I split any table to slave database? The whole process I mean.

Answer 1

If you're building a high-volume Wordpress site, and the database is the bottleneck (as it often is), HyperDB is absolutely the correct Wordpress solution. HyperDB is authored by Automattic, is used on Wordpress.com, and is designed as a proper Wordpress drop-in.
HyperDB supports MySQL read-replicas and partitioning, and which you use depends on your use-case.
These configuration options are actually reasonably well documented in the HyperDB Config file, which looks like this:
https://plugins.trac.wordpress.org/browser/hyperdb/trunk/db-config.php
This won't precisely work for your situation; you'll have to adjust this to fit your setup.
// This is the default database configuration
//
$wpdb->add_database(array(
'host' => 'localhost',
'user' => 'root',
'password' => '',
'name' => 'regular_db',
));
// This is your secondary database.
//
$wpdb->add_database(array(
'host' => 'localhost',
'user' => 'root',
'password' => '',
'name' => 'product_db',
'dataset' => 'products',
));
// This magic detects which database table is being read from/written to, and switches
// hyperdb connection based on that.
$wpdb->add_callback('my_db_product_detector');
function my_db_product_detector($query, $wpdb) {
// This makes the assumption that you've only got one relevant table, wp_products.
// Update this to whatever your table name(s) are.
if ( preg_match('^wp_products$', $wpdb->table) ) {
return 'products';
}
}
To begin with, to test that this works on your existing database, you should change product_db to regular_db, and go from there.
At this point, you have architectural decisions to make. If you simply want to reduce the size of your DB, then this now writes your products to a second DB. Alternatively, you might have a second database server entirely to share the load across different databases.
Creating a read replica is also worth considering, but that depends on what ecosystem you're working with. If you're using AWS, then RDS will create read replicas quite simply.