Re: Parallel Query: lots of wait time in event "PX qref latch"

Thanks for answering.

while watching 'top' for a while, one can see that the load for each PQ slave is about equal. Difficult to check with v$pq_tqstat, because its only the query coordinator who can see this data - and that one is submitted using a scheduler.

What I would've expected, is much more wait time in events like "PX Deq Credit: free buffer", "PX Deq Credit: send blkd". There is some amount of wait time in "PX Deq: Table Q Normal", which is normal.

I am suspicious abut the data for this event is being measured or calculated wrong (probably OS (hp-ux 64-bit) and/or version specific).

Sad that the documentation for this part is far from complete - or wrong.

But, decreasing the degree of parallelism looks like a good alternative.

Kind Regards,

Herman de Boer
IT Consultancy Group bv Received on Fri Nov 02 2001 - 16:16:13 CST