Database cluster

Thank you Marko,

I’m monitoring my reader instance and I don’t see any incoming connections so I guess the db-cluster config is not working somehow…

What do you mean by this?
there should be DB cluster word in footer comment

Do you have a screenshot that can help me find it on my end?

Thanks a lot!

Hi there,

Having the exact same issue as above at the moment. Edited dbcluster-config-sample.php and moved into /wp-content/db-cluster-config.php. But checking the number of connects on the read replica for the past hour and it’s 0.

Also, I can’t see the comment you mention, is it in the source of a particular page?

<?php

global $w3tc_dbcluster_config;

$w3tc_dbcluster_config = array(
	/**
	 * Persistent (bool)
	 *
	 * This determines whether to use mysql_connect or mysql_pconnect. The effects
	 * of this setting may vary and should be carefully tested.
	 * Default: false
	 */
	'persistent' => false,

	/**
	 * check_tcp_responsiveness
	 *
	 * Enables checking TCP responsiveness by fsockopen prior to mysql_connect or
	 * mysql_pconnect. This was added because PHP's mysql functions do not provide
	 * a variable timeout setting. Disabling it may improve average performance by
	 * a very tiny margin but lose protection against connections failing slowly.
	 * Default: true
	 */
	'check_tcp_responsiveness' => true,

	/**
	 * Default is to always (reads & writes) use the master db when user is in administration backend.
	 * Set use_master_in_backend to false to disable this behavior.
	 *
	 * WARNING: if your cluster has any replication delays then when this is enabled, you may not see
	 * any admin changes until the replication catches up with the change written to your master
	 * server and will see old content/configuration until that point in time - You should test this
	 * in your environment fully.
	 */
	'use_master_in_backend' => true,

	/**
	 * This set the charset that the db connection should use.
	 * If DB_CHARSET is set there is no need to set $wpdb_cluster->charset.
	 */
	'charset' => DB_CHARSET,

	/**
	 * This set the charset that the db connection should use.
	 * If DB_COLLATE is set there is no need to set $wpdb_cluster->collate.
	 */
	'collate' => DB_COLLATE,
	/** Configuration Functions **/

	/**
	 * database is an associative array with these parameters:
	 * host             (required) Hostname with optional :port. Default port is 3306.
	 * user             (required) MySQL user name.
	 * password         (required) MySQL user password.
	 * name             (required) MySQL database name.
	 * read             (optional) Whether server is readable. Default is 1 (readable).
	 *			    Also used to assign preference.
	 * write            (optional) Whether server is writable. Default is 1 (writable).
	 *                             Also used to assign preference in multi-master mode.
	 * dataset          (optional) Name of dataset. Default is 'global'.
	 * timeout          (optional) Seconds to wait for TCP responsiveness. Default is 0.2
	 * connect_function (optional) connection function to use
	 * zone             (optional) name of zone where server is located.
	 *                             Used for web applications hosted on cluster
	 *
	 * Read & write
	 * A database definition can include 'read' and 'write' parameters. These
	 * operate as boolean switches but they are typically specified as integers.
	 * They allow or disallow use of the database for reading or writing.
	 *
	 * A master database might be configured to allow reading and writing:
	 *   'write' => true,
	 *   'read'  => true,
	 * while a slave would be allowed only to read:
	 *   'write' => false,
	 *   'read'  => true,
	 *
	 * It might be advantageous to disallow reading from the master, such as when
	 * there are many slaves available and the master is very busy with writes.
	 *   'write' => true,
	 *   'read'  => false,
	 *
	 */

/**
 * 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.
 */

$w3tc_dbcluster_config = array(
	'databases' => array(
		'master' => array(
			'host'     => DB_HOST,
			'user'     => DB_USER,
			'password' => DB_PASSWORD,
			'name'     => DB_NAME
		),
		'slave' => array(
			'host'     => 'read-replica.redacted.eu-west-2.rds.amazonaws.com',
			'user'     => DB_USER,
			'password' => DB_PASSWORD,
			'name'     => DB_NAME,
			'write'    => false,
			'read'     => true,
			'timeout'  => 0.4,
));

Hi Marko and thank you for your message,

Yes, there is a code snippet at the bottom but it seems there is nothing related to ‘DB cluster’:

<!--
Performance optimized by W3 Total Cache. Learn more: https://www.boldgrid.com/w3-total-cache/

Object Caching 0/2 objects using redis
Page Caching using redis
Database Caching using redis (Request-wide modification query)
Fragment Caching 102/180 fragments using redis

Served from: localhost @ 2023-05-19 15:49:06 by W3 Total Cache
-->

The website URL is:
https://trustedd.com

Thank you!

Hi Marko,

Sorry to keep bothering you but just wondering if you’ve had any progress on this one?

Hello, I have been trying to set this configuration up for a while now and haven’t been able to do so…

Just want to add that after reading numerous posts on boldgrid, wodpress.org plugin page and github issues, a solution is never given by w3tc team, all the responses are somehow vague and don’t really provide any clarification or options (a quick search reveals multiple posts reporting this same issue and none of them have a conclusive response from w3tc team.

I actually bought the premium version of the plugin for this feature exclusively, most of us did and after extensive reading and testing I dare to say that said feature does not work at all, it just seems strange to me w3tc team’s reluctance to admit so, and their efforts to just drag the discussions trying to buy time or something like that.

I’ve read posts from over a couple of years a go and none of them have a solution,

Just a plain definitive answer saying this feature is not ready would help us customers to just move on and find another one

In agreement with the above, we purchased the premium version solely for this feature as we can (in theory) run a cluster alongside Memcached whereas HyperDB conflicted with W3TC previously as they both use the db.php file.

Just an idea of current progress or a rough timeframe would be much appreciated.

Hi Marko,

Do you have any updates on this?

Thank you