MySQL Replication is asynchronous which causes problems if you would like to use MySQL Slave as it can contain stale data. It is true delay is often insignificant but in times of heavy load or in case you was running some heavy queries on the master which not take time to replicate to the slave […]
Have you ever seen connection in the SHOW PROCESSLIST output which is in “Sleep” state for a long time and you have no idea why this would happen ? I see if frequently with web applications and it is often indication of trouble. Not only it means you may run out of MySQL connections quicker […]
Article about database design problems is being discussed by Kristian. Both article itself and responce cause mixed feellings so I decided it is worth commenting: 1. Using mysql_* functions directly This is probably bad but I do not like solutions proposed by original article ether. PEAR is slow as well as other complex conectors. I […]
MySQL has a great feature called “Query Cache” which is quite helpful for MySQL Performance optimization tasks but there are number of things you need to know. First let me clarify what MySQL Query Cache is – I’ve seen number of people being confused, thinking MySQL Query Cache is the same as Oracle Query Cache […]
Yesterday we announced the GA release of Percona Server 5.6, the latest release of our enhanced, drop-in replacement for MySQL. Percona Server 5.6 is the best free MySQL alternative for demanding applications. Our third major release, Percona Server 5.6 offers all the improvements found in MySQL 5.6 Community Edition plus scalability, availability, backup, and security […]
Percona XtraDB Cluster (PXC) is different enough from async replication that it can be a bit of a puzzle how to do things the Galera way. This post will attempt to illustrate the basics of setting up 2 node PXC cluster from scratch. Requirements Two servers (could be VMs) that can talk to each other. […]
Today I gave a presentation on “Read/Write Splitting with PHP” for Percona Webinars. If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions. I answered as many as I could during the session, but here are […]
Ever ran into a situation where you saw “some important variable you really needed to know about=<optimized out>” while debugging?
MariaDB 5.3/5.5 has introduced a new join type “Hash Joins” which is an implementation of a Classic Block-based Hash Join Algorithm. In this post we will see what the Hash Join is, how it works and for what types of queries would it be the right choice. I will show the results of executing benchmarks […]
There and in coming posts I am going to cover main features of Percona XtraDB Cluster. The first feature is High Availability. But before jumping to HA, let’s review general architecture of the Percona XtraDB Cluster.