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

[Susanne Moog]

Hi everyone,

we are experiencing some db performance problems. TYPO3 version is 4.2.5 
with the last security fix manually patched.

MySQL log shows thousands of the following queries:

DELETE FROM fe_sessions	WHERE	ses_id = 
'9dd6ed3c54bdf13ea23cb82a7c095831'	AND ses_name = 'fe_typo_user'
DELETE FROM fe_sessions	WHERE	ses_id = 
'bcabb26007a597827d5735e2d4d34f83'	AND ses_name = 'fe_typo_user'
DELETE FROM fe_sessions	WHERE	ses_id = 
'bcabb26007a597827d5735e2d4d34f83'	AND ses_name = 'fe_typo_user'
DELETE FROM fe_sessions	WHERE	ses_id = 
'933e504f3b38d3cbe49839873d05a8aa'	AND ses_name = 'fe_typo_user'

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 ;))

Additional info:
OTHER: TYPO3_VERSION: 4.2.5 (patched)
OTHER: PHP_VERSION  : 5.2.0-8+etch13
MySQL: Client API version 	5.0.32

Any help appreciated,

Susanne