Re: interpreting statspack reports ( PX Deq )

V$pq_tqstat is, as you point out, only visible to the session running the query, and is only populated when a query completes.

For run-time activity, you need to look at a couple of the v$PX_... views. V$PX_STAT gives you a view which lists QC sessions with their PX slaves and effectively joins to v$sesstat for all those sessions. There is another called (I think) v$px_session will just lists the QC and PX sessions under the same QCSID. You can join this one to v$session_wait or v$session_event to watch the waits in real time. If you join to v$session_event, and watch for "PX Deq: Send Blkd" then a 2 second wait is effectively an idle wait, but large numbers of very short waits are performance threats.

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Jonathan Lewis
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Yong Huang wrote in message ...


>Do we have to rely on v$pq_tqstat to find whether the wait Send Blkd

>occurs in the parallel to serial or parallel to parallel stage? If so,

>is it true that we can't see anything in v$pq_tqstat from a session

>other than the one running the parallel query?

>

>Thanks.

>

>