Next week I’m teaching an online Percona Training class, called Analyzing SQL Queries with Percona Toolkit. This is a guided tour of best practices for pt-query-digest, the best tool for evaluating where your database response time is being spent. This month we saw the GA release of MySQL 5.6, and I wanted to check if any [...]
CVE-2012-4414 strikes back in MySQL 5.5.29 (and what we’re doing in Percona Server 5.5.29)
January 13, 2013 By 4 Comments
In preparing Percona Server 5.5.29 (not yet released, but soon), I filed MySQL bug 68045 (is marked private as it’s a security bug). This bug is in relation to the Oracle fix for CVE-2012-4414 and a problem I found with it. The MariaDB fix (which we incorporated into Percona Server 5.5.28-29.3) is not affected. When the [...]
Flexviews – part 3 – improving query performance using materialized views
April 4, 2011 By 20 Comments
Combating “data drift” In my first post in this series, I described materialized views (MVs). An MV is essentially a cached result set at one point in time. The contents of the MV will become incorrect (out of sync) when the underlying data changes. This loss of synchronization is sometimes called drift. This is conceptually [...]
GROUP_CONCAT useful GROUP BY extension
September 4, 2006 By 48 Comments
MySQL has useful extention to the GROUP BY operation: function GROUP_CONCAT: GROUP_CONCAT(expr) – This function returns a string result with the concatenated non-NULL values from a group. Where it can be useful?
