April 24, 2014

10+ Ways to Crash or Overload MySQL

People are sometimes contacting me and asking about bugs like this which provide a trivial way to crash MySQL to the user with basic privileges and asking me what to do. My answer to them is – there is nothing new to it and they just sit should back and relax Really – there are […]

MySQL Prepared Statements

If you care about archiving best performance in your application using MySQL you should learn about prepared statements. These do not neccesary provide performance beneft but they may, they also have other benefits. As a quick introduction – before MySQL 4.1 there were only textual statements and textual protocol for data transfer – query was […]

MySQL EXPLAIN limits and errors.

Running EXPLAIN for problematic queries is very powerful tool for MySQL Performance optimization. If you’ve been using this tool a lot you probably noticed it is not always provide adequate information. Here is list of things you may wish to watch out. EXPLAIN can be wrong – this does not happen very often but it […]

MySQL Server Memory Usage

Every so often people ask me the question how should they estimate memory consumption by MySQL Server in given configuration. What is the formula they could use. The reasons to worry about memory usage are quite understandable. If you configure MySQL Server so it uses too small amount of memory it will likey perform suboptimally. […]

How to add VIPs to Percona XtraDB Cluster or MHA with Pacemaker

It is a rather frequent problem to have to manage Virtual IP addresses (VIPs) with a Percona XtraDB Cluster (PXC) or with MySQL master HA (MHA). In order to help solving these problems, I wrote a Pacemaker agent, mysql_monitor that is a simplified version of the mysql_prm agent. The mysql_monitor agent only monitors MySQL and […]

utf8 data on latin1 tables: converting to utf8 without downtime or double encoding

Here’s a problem some or most of us have encountered. You have a latin1 table defined like below, and your application is storing utf8 data to the column on a latin1 connection. Obviously, double encoding occurs. Now your development team decided to use utf8 everywhere, but during the process you can only have as little […]

InnoDB performance optimization basics (redux)

I recently stumbled upon a post that Peter Zaitsev published back in 2007 titled “Innodb Performance Optimization Basics.” It’s a great post and reading it inspired me to examine what’s changed in the nearly six years that have followed in terms of MySQL, Percona Server – as well as in all of the other now-available […]

Percona XtraDB Cluster 5.5.33-23.7.6 is now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.33-23.7.6 on September 18, 2013. Binaries are available from the downloads area or from our software repositories. New Features: Default State Snapshot Transfer method, defined in wsrep_sst_method variable has been changed from mysqldump to rsync. New wsrep_reject_queries variable has been implemented that can be […]

Adventures in archiving

One of our Remote DBA service clients recently had an issue with size on disk for a particular table; in short this table was some 25 million rows of application audit data with an on disk size of 345GB recorded solely for the purposes of debugging which may or may not occur. Faced with the task of […]

Realtime stats to pay attention to in Percona XtraDB Cluster and Galera

I learn more and more about Galera every day.  As I learn more, I try to keep my myq_gadgets toolkit up to date with what I consider is important to keep any eye on on a PXC node.  In that spirit, I just today pushed some changes to the ‘wsrep’ report, and I thought I’d go over […]