[TYPO3-dev] DB Performance Problems (fe_sessions table)

[Susanne Moog]

Hi Dmitry,

Dmitry Dulepov schrieb:
> Hi!
> 
> Susanne Moog wrote:
>> MySQL log shows thousands of the following queries:
>>
>> DELETE FROM fe_sessions    WHERE    ses_id =
>> '9dd6ed3c54bdf13ea23cb82a7c095831'    AND ses_name = 'fe_typo_user'
> 
> This table should be InnoDB. If it is MyISAM, you will have performance problems.

Hmm, it is already InnoDB. Seems these queries are not the problem then.
I have to look further. Can you (or someone) tell me how to tell for
sure if a plugins output is cached? (Most of our plugins are USER but
where can I take a look if they really are cached?)

> 
>> We do not have frontend users and the table "fe_sessions" is empty. The
>> log does not show any inserts for that table.
>>
>> Can someone give me a hint where and why those queries are generated
>> (and what I can do against it ;))
> 
> TYPO3 creates FE sessions even when user is not logged in. Plugins still can save data in session. So TYPO3 saves sessions and cleans them up from time to time.
> 

Ah thanks for the explanation, I still wonder a bit, why this is the way
it is, as we don't use sessions at all and could happily live without
that (it can't be disabled?).

Thank you for your answer,

Susanne