September 20, 2014

How expensive is USER_STATISTICS?

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. […]

Google’s user_statistics V2 port and changes

Recently Google published V2 release of patches, one of them user_statistics we use in our releases. New features are quite interesting so we decided to port it to fresh releases of MySQL. Features includes: New statistics per user (Cpu_time, Bytes_received, Bytes_sent, etc) New command SHOW CLIENT_STATISTICS, which shows statistics per client’s hostname, not per user […]

When Does InnoDB Update Table Statistics? (And When It Can Bite)

An InnoDB table statistics is used for JOIN optimizations and helping the MySQL optimizer choose the appropriate index for a query. If a table’s statistics or index cardinality becomes outdated, you might see queries which previously performed well suddenly show up on slow query log until InnoDB again updates the statistics. But when does InnoDB […]

How to generate per-database traffic statistics using mk-query-digest

We often encounter customers who have partitioned their applications among a number of databases within the same instance of MySQL (think application service providers who have a separate database per customer organization … or wordpress-mu type of apps). For example, take the following single MySQL instance with multiple (identical) databases:

check-unused-keys: A tool to interact with INDEX_STATISTICS

With the growing adoption of Google’s User Statistics Patch**, the need for supporting scripts has become clear. To that end, we’ve created check-unused-keys, a Perl script to provide a nicer interface than directly querying the INFORMATION_SCHEMA database.

Userstats patches with information schema support

Recently, we added information schema support to Google’s userstats patch. There are three information schema tables added: user_statistics, table_statistics, index_statistics. One can now use select * from information_schema.user_statistics along with show user_statistics. Links: Patch for 5.0.62 Patch for 5.1.26

Percona Server 5.5.38-35.2 is now available

Percona is glad to announce the release of Percona Server 5.5.38-35.2 on July 2, 2014 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.5.38, including all the bug fixes in it, Percona Server 5.5.38-35.2 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details of the release […]

A technical WebScaleSQL review and comparison with Percona Server

The recent WebScaleSQL announcement has made quite a splash in the MySQL community over the last few weeks, and with a good reason. The collaboration between the major MySQL-at-scale users to develop a single code branch that addresses the needs of, well, web scale, is going to benefit the whole community. But I feel that […]

Percona Server 5.5.35-33.0 is now available

Percona is glad to announce the release of Percona Server 5.5.35-33.0 on December 20th, 2013 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.5.35, including all the bug fixes in it, Percona Server 5.5.35-33.0 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details of the release […]

Percona Server 5.1.73-14.11 is now available

Percona is glad to announce the release of Percona Server 5.1.73-14.11 on December 20th, 2013 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.1.73, including all the bug fixes in it, Percona Server 5.1.73-14.11 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 […]