April 16, 2014

On Good Instrumentation

In so many cases troubleshooting applications I keep thinking how much more efficient things could be going if only there would be a good instrumentation available. Most of applications out there have very little code to help understand what is going on and if it is there it is frequently looking at some metrics which […]

Worse than DDOS

Today I worked on rather interesting customer problem. Site was subject what was considered DDOS and solution was implemented to protect from it. However in addition to banning the intruders IPs it banned IPs of web services which were very actively used by the application which caused even worse problems by consuming all apache slots […]

Tools

This page contains links to various tools we found helpful to use in practice. Some tools are written by us, others by third parties, yet another ones may be shipped with your operating system you just need to find they are there. Percona Toolkit Percona Toolkit is a great set of tools for MySQL Performance […]

Updated msl (microslow) patch, installation walk-through!

For a couple of months there have been no updates to our msl patch, however recently I managed some time to change this. The functionality was extended a little bit and what’s even more important the patch is available for all the recent MySQL releases. To remind anyone who has not yet come across this […]

Extended EXPLAIN

One nice feature added for EXPLAIN statement in MySQL 4.1 is EXTENDED keyword which provides you with some helpful additional information on query optimization. It should be used together with SHOW WARNINGS to get information about how query looks after transformation as well as what other notes optimizer may wish to tell us. It is […]

SHOW INNODB STATUS walk through

Many people asked me to publish a walk through SHOW INNODB STATUS output, showing what you can learn from SHOW INNODB STATUS output and how to use this info to improve MySQL Performance. To start with basics SHOW INNODB STATUS is command which prints out a lot of internal Innodb performance counters, statistics, information about […]

How reliable RAID really is

This post is not exactly about MySQL Performance or about Performance at all, but I guess it should be interested to many MySQL DBAs and other people involved running MySQL In production. Recently I’ve been involved in troubleshooting Dell Poweredge 2850 system running RAID5 using 6GB internal hard drives, which give about 1.4TB of usable […]