04 Apr

Anohter way to work with MySQL process list

In an earlier post titled "How to work with a long process list in MySQL", we showed a neat way to work with the process list by using various shell tools. But some of that can also be done using pure SQL.

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03 Apr

Was a query served from MySQL Query Cache?

The MySQL query cache is a special buffer, where database stores the text of a SELECT statement together with the corresponding result that was sent to the client. For as long as no table that a statement refers to changes in any way, including the contents, the cached result can be re-used to answer any identical sub-sequent SELECT statements. But how to tell whether a query was executed or returned from the cache?

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01 Apr

How to find configuration file MySQL uses?

A customer called me today asking for help with locating the configuration file used by one of their production MySQL instances. From the description I was given it appeared that their server had at least six different copies of my.cnf file in different locations on disk. And all were similar enough that each could actually be the one. All superfluous files were the result of a bit negligent system administration. So what turned to be the quickest and the least destructive way to find the correct one?

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