September 2, 2014

About Peter Zaitsev

Peter managed the High Performance Group within MySQL until 2006, when he founded Percona. Peter has a Master's Degree in Computer Science and is an expert in database kernels, computer hardware, and application scaling.

Examining the TokuDB MySQL storage engine file structure

As we know different storage engines in MySQL have different file structures. Every table in MySQL 5.6 must have a .frm file in the database directory matching the table name. But where the rest of the data resides depends on the storage engine. For MyISAM we have .MYI and .MYD files in the database directory […]

Prevent MySQL downtime: Set max_user_connections

One of the common causes of downtime with MySQL is running out of connections. Have you ever seen this error? “ERROR 1040 (00000): Too many connections.” If you’re working with MySQL long enough you surely have. This is quite a nasty error as it might cause complete downtime… transient errors with successful transactions mixed with […]

Why TokuDB hates Transparent HugePages

If you try to install the TokuDB storage engine on a modern Linux distribution it might fail with following error message: 2014-07-17 19:02:55 13865 [ERROR] TokuDB will not run with transparent huge pages enabled. 2014-07-17 19:02:55 13865 [ERROR] Please disable them to continue. 2014-07-17 19:02:55 13865 [ERROR] (echo never > /sys/kernel/mm/transparent_hugepage/enabled) You might be curious […]

Why %util number from iostat is meaningless for MySQL capacity planning

Earlier this month I wrote about vmstat iowait cpu numbers and some of the comments I got were advertising the use of util% as reported by the iostat tool instead. I find this number even more useless for MySQL performance tuning and capacity planning. Now let me start by saying this is a really tricky and deceptive number. Many […]

MySQL Backup Service from Percona

The Percona Backup Service managed service launched today. It ensures properly configured backups run successfully as scheduled on customer provided backup storage – whether on premise, in the cloud, or a hybrid. Backup issues or production data recovery are efficiently handled by Percona Managed Services technicians with deep knowledge of MySQL. As we state in […]

Architecture and Design of MySQL-powered applications: June 11 Webinar

The architecture of MySQL-powered applications is one of my favorite topics to talk about. It’s a very important topic because if you do not get the architecture right then you’re very likely to fail with your project – either from the standpoint of failing with performance, high availability or security requirements… or failing to deliver […]

Do not trust vmstat IOwait numbers

I’ve been running a benchmark today on my old test box with conventional hard drives (no raid with BBU) and noticed something unusual in the CPU utilization statistics being reported. The benchmark was run like this:

Which means: create 64 threads and hammer the database with queries as quickly as possible. As the test […]

How MySQL ‘queries’ and ‘questions’ are measured

MySQL has status variables “questions” and “queries” which are rather close but also a bit different, making it confusing for many people. The manual describing it might not be very easy to understand:

In a nutshell if you’re not using prepared statements the big difference between those is what “Questions” would count stored procedure calls as […]

Practical MySQL performance optimization: May 14 Webinar

Achieving the best possible MySQL Performance doesn’t have to be complicated. It’s all about knowing which tools are designed for the task at hand – along with some basic (yet often overlooked) best practices. Join me Wednesday, May 14 at 10 a.m. Pacific for a free webinar titled, “Practical MySQL performance optimization.” I’ll be sharing […]

Percona University @Montevideo, FISL & São Paulo MySQL Meetup

Later this week I’m excited to depart on a trip to South America. First I will stop in Montevideo, Uruguay, to meet with Percona’s team out there as well as to participate in our next Percona University event on April 29. For those who do not know, Percona University events are free to attend and […]