July 28, 2014

MySQL server memory usage troubleshooting tips

There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a Percona support engineer, I’m seeing many issues regularly related to heavy server loads – OR OOM killer got invoked and […]

Renaming database schema in MySQL

One of the routine tasks for a DBA is renaming database schemas, and as such MySQL added a command to carry out that purpose called “RENAME DATABASE <database_name>”. However this command just made it through a few minor releases before being discontinued (from MySQL 5.1.7 to 5.1.23). Here’s a link to the reference manual regarding […]

How to Extract All Running Queries (Including the Last Executed Statement) from a Core File?

This post builds on the How to obtain the “LES” (Last Executed Statement) from an Optimized Core Dump? post written about a year ago. A day after that post was released, Shane Bester wrote an improved version, How to obtain all executing queries from a core file on his blog. Reading that post is key […]

The power of MySQL’s GROUP_CONCAT

In the very early days of Percona Vadim wrote very nice post about GROUP_CONCAT. But I want to show you a bit more about it. When is GROUP_CONCAT useful? Usually while working with Support customers I recommend it when you have aggregation of many-to-many info. It makes the view simpler and more beautiful and it […]

SSL Performance Overhead in MySQL

NOTE: This is part 1 of what will be a two-part series on the performance implications of using in-flight data encryption. Some of you may recall my security webinar from back in mid-August; one of the follow-up questions that I was asked was about the performance impact of enabling SSL connections. My answer was 25%, […]

Want to archive tables? Use Percona Toolkit’s pt-archiver

Percona Toolkit’s pt-archiver is one of the best utilities to archive the records from large tables to another tables or files. One interesting thing is that pt-archiver is a read-write tool. It deletes data from the source by default, so after archiving you don’t need to delete it separately. As it is done by default, you […]

When it’s faster to use SQL in MySQL NDB Cluster over memcache API

Memcache access for MySQL Cluster (or NDBCluster) provides faster access to the data because it avoids the SQL parsing overhead for simple lookups – which is a great feature. But what happens if I try to get multiple records via memcache API (multi-GET) and via SQL (SELECT with IN())? I’ve encountered this a few times […]

tpcc-mysql: Simple usage steps and how to build graphs with gnuplot

Lots of times we could see different benchmarks performed by tpcc-mysql. So today I want to tell you about how to use tpcc-mysql and how to build graphs with gnuplot in a few easy steps. As an example I’ll compare Percona Server 5.5 (latest version: 5.5.31) performance by changing InnoDB buffer pool size: innodb_buffer_pool_size = […]

Setting up MySQL SSL and secure connections

There are different articles on how to setup MySQL with SSL but it’s sometimes difficult to end up with a good simple one. Usually, setting up MySQL SSL is not really a smooth process due to such factors like “it’s not your day”, something is broken apparently or the documentation lies I am going to […]

Migrating between MySQL schemas with Percona Xtrabackup

Recently, I was working with a client that asked about using Percona Xtrabackup to take a snapshot of a particular MySQL schema and then reload it with a different schema name on the same server.  It caught me off guard because I’d never really thought about it – typically, I’ve used Xtrabackup simply to clone […]