[TYPO3-performance] Backend Performance TYPO3 4.3 - Strange Behavior

[R. van Twisk]

On Wed, 02 Jun 2010 16:54:26 +0300, Dmitry Dulepov wrote:

> Hi!
> 
> Thomas "Thasmo" Deinhamer wrote:
>> if indexes/keys won't slow down 'small' sites, it's a good idea to
>> introduce indexes/keys
> 
> There are several issues here... Many indexes will actually slow down
> the site because:
> - they all have to be checked and updated when the table is changed -
> they all will be considered for the query when query is executed
> 
> Making good keys is not easy because it requires observation of a real
> data. With some dummy data it is not possible to find good indexes. I
> used to make different indexes on different sites depending on site
> specifics...

For all tables that are mostly read (90% read) it's not a big issue to
have more indexes to speed up BE read operations. For these times you 
need to write as a BE user it's 'ok' to wait a tad longer to let the write
operation to finish, as long it's not seconds... bit if it takes seconds, 
you have bigger problems then just a index.

Care most be taken to add indexes to tables that are frequently written 
to, like log tables (sys_log), cache tables (cache_XXX)

Dmitry is right about using real world data, random data to test indexes 
won't do it under some conditions.