Monthly Archives - February 2012

DBD::mysql 4.014 breaks pt-table-checksum 2.0

DBD::mysql 4.014 breaks pt-table-checksum 2.0.  The cause is unknown, but the effect is a lot of errors like:
DBD::mysql::st execute failed: called with 2 bind variables when 6 are needed [for Statement “…” with ParamValues: …] at ./pt-table-checksum line 7216.
The fix is simple: upgrade (or even downgrade) DBD::mysql to any version except 4.014. To see […]

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How to convert MySQL’s SHOW PROFILES into a real profile

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 […]

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MariaDB 5.3.4 benchmarks

MariaDB 5.3 has reached the release candidate milestone, and the 5.3 version promises a lot of new features and optimization (i.e in optimizer http://kb.askmonty.org/en/what-is-mariadb-53#query-optimizer). No surprise I wanted to check how all improvements affect general performance.
So I why don’t we run old good sysbench benchmark.
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Can we improve MySQL variable handling ?

MySQL Settings (also known as Server Variables) have interesting property. When you set variable in running server this change is not persisted in any way and server will be back to old value upon restart. MySQL also does not have option to re-read config file without restarting as some other software so approach […]

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The relationship between Innodb Log checkpointing and dirty Buffer pool pages

This is a time-honored topic, and there’s no shortage of articles on the topic on this blog. I wanted to write a post trying to condense and clarify those posts, as it has taken me a while to really understand this relationship.
Some basic facts

Most of us know that writing into Innodb updates buffer pool […]

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