Monthly Archives - July 2015

How to obtain the MySQL version from an FRM file

I recently helped a customer figure out why a minor version MySQL upgrade was indicating that some tables needed to be rebuilt. The mysql_upgrade program should be run for every upgrade, no matter how big or small the version difference is, but when only the minor version changes, I would normally not expect it […]

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MySQL QA Episode 4: QA Framework Setup Time!

Welcome to MySQL QA Episode 4! In this episode we’ll look into setting up our QA Framework: percona-qa, pquery, reducer & more.
1. All about percona-qa
2. pquery

Shell

$ cd ~; bzr branch lp:percona-qa

1

$ cd ~; bzr branch lp:percona-qa

3. reducer.sh

Shell

$ cd ~; bzr branch lp:randgen
$ vi ~/randgen/util/reducer/reducer.sh

12

$ cd ~; bzr branch lp:randgen$ vi ~/randgen/util/reducer/reducer.sh

4. Short introduction to pquery […]

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MySQL QA Episode 3: How to use the debugging tool GDB

Welcome to MySQL QA Episode 3: “Debugging: GDB, Backtraces, Frames and Library Dependencies”
In this episode you’ll learn how to use debugging tool GDB. The following debugging topics are covered:
1. GDB Introduction
2. Backtrace, Stack trace
3. Frames
4. Commands & Logging
5. Variables
6. Library dependencies
7. c++filt
8. Handy references
– GDB Cheat sheet (page #2): https://goo.gl/rrmB9i
– From Crash to testcase: https://goo.gl/3aSvVW
Also expands on […]

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TOI wsrep_RSU_method in PXC 5.6.24 and up

I noticed that in the latest release of Percona XtraDB Cluster (PXC), the behavior of wsrep_OSU_method changed somewhat.  Prior to this release, the variable was GLOBAL only, meaning to use it you would:

Shell

mysql> set GLOBAL wsrep_OSU_method=’RSU’;
mysql> ALTER TABLE …
mysql> set GLOBAL wsrep_OSU_method=’TOI’;

123

mysql> set GLOBAL wsrep_OSU_method=’RSU’;mysql> ALTER TABLE …mysql> set GLOBAL wsrep_OSU_method=’TOI’;

This had the (possibly […]

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Percona Server 5.5.44-37.3 is now available

Percona is glad to announce the release of Percona Server 5.5.44-37.3 on July 1, 2015. Based on MySQL 5.5.44, including all the bug fixes in it, Percona Server 5.5.44-37.3 is now the current stable release in the 5.5 series.
Percona Server is open-source and free. Details of the release can be found in the 5.5.44-37.3 […]

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Percona Server 5.6.25-73.0 is now available

Percona is glad to announce the release of Percona Server 5.6.25-73.0 on July 1, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories.
Based on MySQL 5.6.25, including all the bug fixes in it, Percona Server 5.6.25-73.0 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source […]

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Using Cgroups to Limit MySQL and MongoDB memory usage

Quite often, especially for benchmarks, I am trying to limit available memory for a database server (usually for MySQL, but recently for MongoDB also). This is usually needed to test database performance in scenarios with different memory limits. I have physical servers with the usually high amount of memory (128GB or more), but I […]

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