Why siebel is creating large logs

We have a situation where siebel creates logs of all sqls in the enterprise log folder. This happens although log levels have been reduced to 1. Also when I want to analyse performance issues and mark all performance events to log level 4 for the object manager, then i see no effect on the log files. There is no logs of performance events, instead they are the same sqls as before.

How can the sql statements be stopped. They are all entered in the S DOCL TXN LOG table and after a point that table overfills and after that no more activity is possible on any siebel session unless the table is truncated.