July 30, 2014

Q&A: Even More Deadly Mistakes of MySQL Development

On Wednesday I gave a presentation on “How to Avoid Even More Common (but Deadly) MySQL Development Mistakes” for Percona MySQL 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 we had […]

Innotop: A real-time, advanced investigation tool for MySQL

GUI monitoring tools for MySQL are not always suitable for all our needs or situations. Most of them are designed to provide historical views into what happens to our database over time rather then real-time insight into current MySQL server status. Excellent free tools for this include Cacti, Zabbix, Ganglia, Nagios, etc. But each of […]

Why is the ibdata1 file continuously growing in MySQL?

We receive this question about the ibdata1 file in MySQL very often in Percona Support. The panic starts when the monitoring server sends an alert about the storage of the MySQL server – saying that the disk is about to get filled. After some research you realize that most of the disk space is used […]

Reasons for run-away main Innodb Tablespace

So you’re running MySQL With innodb_file_per_table option but your ibdata1 file which holds main (or system) tablespace have grown dramatically from its starting 10MB size. What could be the reason of this growth and what you can do about it ? There are few things which are always stored in main tablespace – these are […]

Some little known facts about Innodb Insert Buffer

Despite being standard Innodb feature forever Insert Buffers remains some kind of mysterious thing for a lot of people, so let me try to explain thing a little bit. Innodb uses insert buffer to “cheat” and not to update index leaf pages when at once but “buffer” such updates so several updates to the same […]

Can Innodb Read-Ahead reduce read performance ?

I ran into pretty interesting behavior today. We needed to dump and reload large database and we had pretty good IO subsystem so we started number of mysqldump processes in parallel. Unlike in other case when we did load in parallel, dump in parallel did not increase IO rate significantly and we could still see […]

Magic Innodb Recovery self healing

We have certain type of the table corrupting with Innodb, as it is limited to only one particular index on one particular table type it is likely to be Innodb bug but Heikki currently could not find what could be causing it. Happily as we have data stored in many tables of same format rather […]

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 […]

Recovery deleted ibdata1

Recently I had a case when a customer deleted the InnoDB main table space – ibdata1 – and redo logs – ib_logfile*. MySQL keeps InnoDB files open all the time. The following recovery technique is based on this fact and it allowed to salvage the database. Actually, the files were deleted long time ago – […]

Tuning for heavy writing workloads

For the my previous post, there was comment to suggest to test db_STRESS benchmark on XtraDB by Dimitri. And I tested and tuned for the benchmark. I will show you the tunings. It should be also tuning procedure for general heavy writing workloads. At first, <tuning peak performance>. The next, <tuning purge operation> to stabilize […]