Oracle Database Discussions

Dear All,

This is a 10.2.0.3 version. I have a situation where customer is running few batch jobs at the same time. This causes serious "free buffer waits". Those batch jobs running a few statement joining large tables (some 1Gb, some 400-500Mb).

As tuning the query is not possible at this point since this would require redesign the whole program. Thus i was thinking of increasing the buffer cache as well and start more db writer process (just additional one more).

Is it rational to start more db writer if we increase the buffer cache if we have this free buffer waits coming at the top of top 5 wait events?

Most of the joins involved hash joins due to the large data and another approach is to increase the pga_aggregate_target. But i came across note saying only 5% will be used and we have to set the undocumented parameter(_pga_max_size) if want to super-sized your. I just wandering if there is any catch here that i should be aware of?

Thanks