[TYPO3-dev] Testing TYPO3 caching vs.[FE][pageCacheToExternalFiles]

[Martin Kutschker]

Dmitry Dulepov schrieb:
> Hi!
> 
> Martin Kutschker wrote:
> 
>>To convince me you must show me an index and the explains for real-world
>>selects of TYPO3 :-)
> 
> 
> EXPLAIN is only a guess. It is not authorative and depends on the
> current state of the database, number of records, "ANALYZE" status, etc.

Huh? But you can only make indices for your data. EXPLAIN tells you 
something about the data and what Mysql thinks of it.

Adding indices without checking EXPLAIN before and after making changes to 
indices is IMHO only wild guessing.

Anyway, you probably need more than 1000 rows to see a real difference for 
simple queries. TYPO3 doesn't do funny joins, so I still like to see a) the 
new indices and b) the affected queries. Adding some indices and hoping 
that a few of them increase perfomance is not enough. If we want to tune we 
must know what changes bring what benefits. This is where EXPLAIN will help.

Masi

PS: Don't forget that various chaches in Mysql and in the OS affect your 
tests! A rerun may show different results.