September 16, 2014

Percona XtraDB Cluster 5.5.39-25.11 is now available

Percona is glad to announce the new release of Percona XtraDB Cluster 5.5 on September 5th 2014. Binaries are available from downloads area or from our software repositories. Based on Percona Server 5.5.39-36.0 including all the bug fixes in it, Galera Replicator 2.11, and on Codership wsrep API 25.11, Percona XtraDB Cluster 5.5.39-25.11 is now […]

Percona XtraDB Cluster 5.5.37-25.10 is now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.37-25.10 on May 8, 2014. Binaries are available from the downloads area or from our software repositories. Based on Percona Server 5.5.37-35.0 including all the bug fixes in it, Galera Replicator 2.10 (including fixes in 2.9 and 2.10 milestones) and on wsrep API 25.10 […]

Announcing Percona Server 5.1.66-14.1

Percona is glad to announce the release of Percona Server 5.1.66-14.1 on October 26th, 2012 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.1.66, including all the bug fixes in it, Percona Server 5.1.66-14.1 is now the current stable release in the 5.1 series. All of Percona‘s software is open-source and free, all the details of the release can […]

Percona Server 5.1.59-13.0

Percona is glad to announce the release of Percona Server 5.1.59-13.0 on October 15, 2011 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.1.59, including all the bug fixes in it, Percona Server 5.1.59-13.0 is now the current stable release in the 5.1 series. All of Percona’s software is open-source and free, all the […]

When EXPLAIN estimates can go wrong!

I have been working with a few customer cases and one interesting case popped up. The customer was facing a peculiar problem where the rows column in the EXPLAIN output of the query was totally off. The actual number of rows was 18 times more than the number of rows reported by MySQL in the […]

MySQL 6.0 vs 5.1 in TPC-H queries

Last week I played with queries from TPC-H benchmarks, particularly comparing MySQL 6.0.4-alpha with 5.1. MySQL 6.0 is interesting here, as there is a lot of new changes in optimizer, which should affect execution plan of TPC-H queries. In reality only two queries (from 22) have significantly better execution time (about them in next posts), […]

Tools and tips for analysis of MySQL’s Slow Query Log

MySQL has a nice feature, slow query log, which allows you to log all queries that exceed a predefined about of time to execute. Peter Zaitsev first wrote about this back in 2006 – there have been a few other posts here on the MySQL Performance Blog since then (check this and this, too) but […]

Recovering temporal types in MySQL 5.6: TIME, TIMESTAMP and DATETIME

MySQL 5.6 introduces a new feature – microseconds resolution in some temporal types. As of 5.6.4 TIME, TIMESTAMP and DATETIME can have a fractional part. To create a field with subseconds you can specify precision in brackets: TIME(3), DATETIME(6) etc. Obviously, the new feature requires the format change. All three types may now have a […]

Schema changes – what’s new in MySQL 5.6?

Among many of the improvements you can enjoy in MySQL 5.6, there is one that addresses a huge operational problem that most DBAs and System Administrators encounter in their life: schema changes. While it is usually not a problem for small tables or those in early stages of product life cycle, schema changes become a […]

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 […]