SHOW PROFILES shows how much time MySQL spends in various phases of query execution, but it isn’t a full-featured profile. By that, I mean that it doesn’t show similar phases aggregated together, doesn’t sort them by worst-first, and doesn’t show the relative amount of time consumed. I’ll profile the “nicer_but_slower_film_list” included with the Sakila sample [...]
Troubleshooting MySQL Upgrade Performance Regressions
February 15, 2012 By Leave a Comment
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 [...]
Beware the Innodb Table Monitor
November 29, 2011 By 2 Comments
As I stated in my last post, I decided to use the Innodb Table monitor to diagnose an Index count mismatch error a customers found in their mysqld.err log to verify if the problem still existed. The Innodb Table Monitor has existed for basically forever in Innodb (the MySQL manual discusses it back in the 4.1 [...]
Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
It is no secret that bugs related to multithreading–deadlocks, data races, starvations etc–have a big impact on application’s stability and are at the same time hard to find due to their nondeterministic nature. Any tool that makes finding such bugs easier, preferably before anybody is aware of their existence, is very welcome.
Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
Shard-Query is an open source tool kit which helps improve the performance of queries against a MySQL database by distributing the work over multiple machines and/or multiple cores. This is similar to the divide and conquer approach that Hive takes in combination with Hadoop. Shard-Query applies a clever approach to parallelism which allows it to [...]
Percona Server and XtraBackup weekly news, March 19th
March 20, 2011 By 2 Comments
Here’s what is new in Percona Server and Percona XtraBackup since last week. We are working on compiling and checking download statistics for both pieces of software. The preliminary numbers are far higher than I thought they would be. Both Percona Server and XtraBackup are becoming amazingly popular. I am aware of deployments running into [...]
Pretty-formatted index fragmentation with xtrabackup
March 15, 2011 By 4 Comments
The xtrabackup compiled C binary (as distinct from XtraBackup, which is the combination of the C binary and the Perl script) has support for printing out stats on InnoDB tables and indexes. This can be useful to examine whether you’d benefit from “defragmenting” your MySQL database with OPTIMIZE TABLE, although I have not determined firm [...]
MySQL on Amazon RDS part 1: insert performance
March 15, 2011 By 37 Comments
Amazon’s Relational Database Service (RDS) is a cloud-hosted MySQL solution. I’ve had some clients hitting performance limitations on standard EC2 servers with EBS volumes (see SSD versus EBS death match), and one of them wanted to evaluate RDS as a replacement. It is built on the same technologies, but the hardware and networking are supposed [...]
Percona Server 5.1.49-rel12.0
September 15, 2010 By 6 Comments
Dear Community, Starting with this release, we introduce a new release model for Percona Server. From now on, we will have both Stable and Release Candidate releases. Release Candidates will introduce new features not yet available in Stable releases. Along with new features, our new 5.1.49-12.0 RC contains a couple of patches from the Facebook-MySQL [...]
Analyzing the distribution of InnoDB log file writes
July 16, 2010 By 5 Comments
I recently did a quick analysis of the distribution of writes to InnoDB’s log files. On a high-traffic commodity MySQL server running Percona XtraDB for a gaming workload (mostly inserts to the “moves” table), I used strace to gather statistics about how the log file writes are distributed in terms of write size. InnoDB writes [...]
