October 20, 2014

When EXPLAIN can be misleading

One think I can see with people using EXPLAIN is trusting it too much, ie assuming if number of rows is reported by EXPLAIN is large query must be inefficient. It may not be the case. The question is not only about stats which may be wrong and which is why you may want to […]

Undo area size restriction needed for Innodb

As you can read from my Innodb Architecture and Performance Optimization presentation Innodb automatically manages undo area in system tablespace so you never need to care about it. I present it as positive feature reducing administration effort needed but it also can cause a troubles as it happened for me today: InnoDB: 11 transaction(s) which […]

Back from OpenSource Database Conference

I’m just back from OpenSource Database Conference and PHP International Conference which took place in Frankfurt. I’ve uploaded slides for two talks I’ve been giving which you might want to check out. In general Database portion of the conference was a bit boring. May be because it was not widely announced or may be for […]