Are PHP persistent connections evil ?

As you probably know PHP “mysql” extension supported persistent connections but they were disabled in new “mysqli” extension, which is probably one of the reasons some people delay migration to this extension.
The reason behind using persistent connections is of course reducing number of connects which are rather expensive, even though they are […]

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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) […]

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