Ragarding Schema Stats

Sir sometime i faced the performance problem and i observed that the statistics for CBO are stale and i run the package
dbms_stats.gather_schema_stats('NSL');
but the problem become even much severe
Can u please guide me what could be the reason ?
thanx in advance

have you done all your ground works and after that you are in a position to say that statsitics is the culprit.

If that's the case, then talk to support.

Otherwise take the trace of the sql and then analyze the query.