To recover a dropped or corrupt table with Percona Data Recovery Tool for InnoDB you need two things: media with records(ibdata1, *.ibd, disk image, etc.) and a table structure. Indeed, there is no information about the table structure in an InnoDB page. Normally we either recover the structure from .frm files or take it from [...]
Is your MySQL buffer pool warm? Make it sweat!
April 16, 2013 By 6 Comments
Today’s blog post diving into the waters of the MySQL buffer pool is a cross-post from Groupon’s engineering blog, and is Part 1 of 2. Thank you to Kyle Oppenheim at Groupon for contributing to this project and post. We’ll be posting Part 2 on Thursday. I’ll be at the Percona Live MySQL Conference and [...]
Fun with the MySQL pager command
January 21, 2013 By 6 Comments
Last time I wrote about a few tips that can make you more efficient when using the command line on Unix. Today I want to focus more on pager. The most common usage of pager is to set it to a Unix pager such as less. It can be very useful to view the result [...]
Measuring the amount of writes in InnoDB redo logs
October 8, 2012 By 4 Comments
Choosing a good InnoDB log file size is key to InnoDB write performance. This can be done by measuring the amount of writes in the redo logs. You can find a detailed explanation in this post. To sum up, here are the main points: The redo logs should be large enough to store at most [...]
News Flash: SQL Injection Still a Problem
July 18, 2012 By 3 Comments
The threat of SQL injection has appeared prominently in the news recently: An SQL injection vulnerability resulted in an urgent June bugfix release of Ruby on Rails 3.x. Make sure you upgrade if you use Rails 3.0, 3.1, or 3.2! Also you should disable mass assignment in any Rails project. Yahoo! Voices was hacked in July. The [...]
How expensive is USER_STATISTICS?
June 2, 2012 By 14 Comments
One of our customers asked me whether it’s safe to enable the so-called USER_STATISTICS features of Percona Server in a heavy-use production server with many tens of thousands of tables. If you’re not familiar with this feature, it creates some new INFORMATION_SCHEMA tables that add counters for activity on users, hosts, tables, indexes, and more. [...]
ext4 vs xfs on SSD
March 15, 2012 By 26 Comments
As ext4 is a standard de facto filesystem for many modern Linux system, I am getting a lot of question if this is good for SSD, or something else (i.e. xfs) should be used. Traditionally our recommendation is xfs, and it comes to known problem in ext3, where IO gets serialized per i_node in O_DIRECT [...]
An update on Percona Live MySQL Conference & Expo 2012
November 30, 2011 By 2 Comments
We announced a while back that we were going to continue the traditional MySQL conference in Santa Clara, because O’Reilly wasn’t doing it anymore. But we haven’t given an update in a while. Here’s the current status: We created a conference committee. We created a conference website that allows people to create an account and [...]
Dynamic row format for MEMORY tables
September 6, 2011 By 5 Comments
The latest Percona Server release has one new feature: now MEMORY tables can have BLOB and TEXT columns, and VARCHAR columns will not waste space due to implicit extension to CHAR.
Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
Can Shard-Query scale to 20 nodes? Peter asked this question in comments to to my previous Shard-Query benchmark. Actually he asked if it could scale to 50, but testing 20 was all I could due to to EC2 and time limits. I think the results at 20 nodes are very useful to understand the performance: [...]
