Re: PX Deq: Table Q qref

All

I have some more information on this. I turned on event 10046 on this. From this I was able to note the following...

1. I start the sql script and spool the results
2. It waits for less than a second on "process startup" and "PX Deq: Join ACK". I think these are waits for starting up the parallel query slaves and then they acknowledging the startup.
3. Then it starts waiting on "PX Deq Credit: need buffer" and "PX Deq Credit: send blkd". I think these are when PQ actually returns data to the QC
4. Then it starts witing on "PX Deq: Execute Reply". I see numerous waits on this. I am not sure on what this wait means.

5.After two hours, it starts waiting on "PX Deq: Table Q qref" and "SQL*Net message to client". By this time, it has finished writing to the spool file. I verified this from the unix timestamp. The trace also shows "FETCH #1:c=0,e=0,p=0,cr=0,cu=0,mis=0,r=15,dep=0,og=4,tim=57419669"

6. After about 3-4 hours later the SQL prompt returns to me. During this time it has not written to the spool file. So I am not sure what is being done in this time...

What is it doing during the Step5 desciribed above? Also why does it show "Fetch" when I have already gotten the data..

Can any of you pl comment on the above... Am I missing anything or am I interpreting it wrong...

Thanks a lot

Babu
----- Original Message -----
To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Thursday, April 11, 2002 4:03 AM

>
> Not entirely sure, but I think this is a query slave
> trying to make, or break a link from another layer
> in the DFO.
>
> As the query gets to completion, I would expect
> to see the QC gathering results, and the slaves
> either in:
> PX Deq Send Blkd (i.e. more data to send
> but another slave is currently passing data
> to the QC)
> or
> PX Deq Execution message (roughly, this is
> from memory) which means all its data has
> been transmitted and it is waiting for a message
> from the QC to tell it to die.
>
>
>
> Jonathan Lewis
> http://www.jlcomp.demon.co.uk
>
> Host to The Co-Operative Oracle Users' FAQ
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
> Author of:
> Practical Oracle 8i: Building Efficient Databases
>
>
> -----Original Message-----
> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> Date: 10 April 2002 18:05
>
>
> All
>
> What does this wait event mean? I have a process that connects to the
> database through ODBC and this process is waiting on this event and
> SQL*Net message from client.
>
> Often this process waits for an unreasonable amout of time (40000
> seconds or more) on SQL*Net MEssage from client and PX Deq: Table Q
> qref before it successfully completes...
>
> TIA
>
> Babu
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Jonathan Lewis
> INET: jonathan_at_jlcomp.demon.co.uk
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Babu Nagarajan
  INET: orclbabu_at_hotmail.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
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