April 20, 2014

Profiling MySQL Memory Usage With Valgrind Massif

There are times where you need to know exactly how much memory the mysqld server (or any other program) is using, where (i.e. for what function) it was allocated, how it got there (a backtrace, please!), and at what point in time the allocation happened. For example; you may have noticed a sharp memory increase […]

Review of MySQL 5.6 Defaults Changes

James Day just posted the great summary of defaults changes in MySQL 5.6 compared to MySQL 5.5 In general there are a lot of good changes and many defaults are now computed instead of hardcoded. Though some of changes are rather puzzling for me. Lets go over them: back_log = 50 + ( max_connections / […]

Percona Server vs MySQL on Intel 320 SSD

If you are terrified by the stability of the results in MySQL in my previous post, I am going to show what we can get with Percona Server. This is also to address the results presented there Benchmarking MariaDB-5.3.4

Can we improve MySQL variable handling ?

MySQL Settings (also known as Server Variables) have interesting property. When you set variable in running server this change is not persisted in any way and server will be back to old value upon restart. MySQL also does not have option to re-read config file without restarting as some other software so approach to change […]

Troubleshooting MySQL Upgrade Performance Regressions

So lets say you upgraded from MySQL 5.1 to Percona Server 5.5 and instead of expected performance improvement you see your performance being worse. What should you do ? First if you followed MySQL upgrade best practices such as testing your workload with pt-upgrade the chances of this happening are rather slim. But lets assume […]

Online MySQL Configuration Wizard from Percona

Merry Christmas! Just in time for the holidays, we have released a new tool to help you configure and manage your MySQL servers. Our online MySQL Configuration Wizard can help you generate a good basic configuration file for a server. This MySQL tuning wizard is our answer to the commonly asked question, “what is a […]

Should MySQL update the default innodb_log_file_size?

Now that InnoDB is the default storage engine in MySQL, is it time to update the default configuration for the InnoDB log file size (innodb_log_file_size) setting? In general, there are two settings that simply can’t be left at their historical defaults for a production installation. MySQL 5.5 increased the default buffer pool size to something […]

What’s required to tune MySQL?

I got a serendipitous call (thanks!) yesterday asking what would be needed to tune[1] a database for better performance. It is a question that I hear often, but I never thought about answering it in public. Here’s a consolidated version of what I explained during our conversation.

Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2

Part of the InnoDB duties, being an MVCC-implementing storage engine, is to get rid of–purge–the old versions of the records as they become obsolete.  In MySQL 5.1 this is done by the master InnoDB thread.  Since then, InnoDB has been moving towards the parallelized purge: in MySQL 5.5 there is an option to have a […]

How Percona diagnoses MySQL server stalls

We receive many requests for help with server stalls. They come under various names: lockup, freeze, sudden slowdown. When something happens only once or twice a day, it can be difficult to catch it in action. Unfortunately, this often leads to trial-and-error approaches, which can drag on for days (or even months), and cause a […]