Over the last months I’ve seen lots of customers trying to tune the thread concurrency inside MySQL with the variable thread_concurrency. Our advice is: stop wasting your time, it does nothing on GNU/Linux Some of the biggest GNU/Linux distributions includes the variable thread_concurrency in their my.cnf file by default. One example is Debian and its [...]
Data compression in InnoDB for text and blob fields
May 30, 2012 By 2 Comments
Have you wanted to compress only certain types of columns in a table while leaving other columns uncompressed? While working on a customer case this week I saw an interesting problem where a table had many heavily utilized TEXT fields with some read queries exceeding 500MB (!!), and stored in a 100GB table. In this [...]
Secure passwords being insecure
May 27, 2012 By 6 Comments
If you follow the general advices to create secure password the following ones seem to be secure, right? s11P$||!sh&2 pr0&!!ke0 3kj39|!381 The answer to the question is, “it depends on how you use them” Notice that these passwords all contain multiple exclamation points and ampersands which are normally special characters for your shell. The people [...]
Binary log file size matters (sometimes)
May 24, 2012 By 6 Comments
I used to think one should never look at max_binlog_size, however last year I had a couple of interesting cases which showed that sometimes it may be very important variable to tune properly. I meant to write about it earlier but never really had a chance to do it. I have it now!
Can we improve MySQL variable handling ?
February 18, 2012 By 8 Comments
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 [...]
Why not make a tool to improve existing configurations?
February 10, 2012 By 4 Comments
A couple of users of our very popular MySQL Configuration Wizard have submitted feedback such as “I’d love to input my existing server settings and get suggestions on how to improve it.” This sounds like it would be great, doesn’t it? We’ve considered doing this, and even partially implemented it. But during our pre-release testing, [...]
MySQL Configuration Wizard Updated
January 26, 2012 By 5 Comments
We’ve released an updated version of the MySQL Configuration Wizard we announced at the end of last year. If you don’t remember that announcement, here’s the short version: this is a tool to help you generate my.cnf files based on your server’s hardware and other characteristics. We’ve gotten really good feedback on this tool, including [...]
How to recover a single InnoDB table from a Full Backup
January 25, 2012 By 10 Comments
Sometimes we need to restore only some tables from a full backup maybe because your data loss affect a small number of your tables. In this particular scenario is faster to recover single tables than a full backup. This is easy with MyISAM but if your tables are InnoDB the process is a little bit [...]
Percona Replication Manager, a solution for MySQL high availability with replication using Pacemaker
November 29, 2011 By 102 Comments
The content of this article is outdated, look here for more up to date information. Over the last year, the frustration of many of us at Percona regarding issues with MMM has grown to a level where we started looking at other ways of achieving higher availability using MySQL replication. One of the weakness of [...]
Getting MySQL Core file on Linux
August 26, 2011 By 1 Comment
Core file can be quite helpful to troubleshoot MySQL Crashes yet it is not always easy to get, especially with recent Linux distributions which have security features to prevent core files to be dumped by setuid processes (and MySQL Server is most commonly ran changing user from “root” to “mysql”). Before you embark on enabling [...]
