Re: PX Deq wait

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Wed, 9 Jun 2004 16:12:37 +0100
Message-ID: <023001c44e34$365fcb10$7102a8c0@Primary>

I have a note about this lurking somewhere, but can't find it so you'll have to take this from memory, and I can't guarantee it's right.

>From v$event_name, p1raw is the blocker or the
wait time. But the rules of interpretation are not given.

I THINK:
The low 4 digits is the slave number of the blocker. (as in Pnnn, not the SID) or FFFF for the query coordinator.

Somewhere in there, there is a clue about the wait time - and I think it depends on the top bit: there is a 'non-contentious' wait time of 200 centiseconds, (0xC8) and any other time is a contentious time. (A 'non-contentious' wait time example: if the QC is reading an order input from the slaves, the first will be supplying, and the others will be idling with a 2-second wakeup, awaiting there turn)

So if you can see the slave that's being wait for, and a 0xC8 in the high word, then the slave is twiddling it's thumbs waiting to be told that it is time to supply date.

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk

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Original Message ----- From: "David Sharples" <dsharples_at_cerebrussolutions.com> To: <oracle-l_at_freelists.org> Sent: Wednesday, June 09, 2004 1:46 PM Subject: PX Deq wait

Hi, had a little problem today.

Had a process which had been running for over 24 hours (should take about 15 secs) it was waiting on PX Deq Credit: send blkd.

It was a job which did some inserts, statspack was telling me no i/o was being done on the objects at all. Is it possible that the parallel slaves had died so my process never knew it had finished, no trace files were generated and nothing in the alert log, killing the process and restarting it fixed it

Is there somewhere else I can look next time to see what has really happened?

Thanks

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Received on Wed Jun 09 2004 - 10:09:32 CDT