RE: Implement Parallel Processing on DB Warehouse

From: Freeman, Donald <dofreeman_at_state.pa.us>
Date: Wed, 11 Feb 2004 10:17:55 -0500
Message-ID: <AFF54B073FF15849B53E32E67EE860763A7C8F@ENHBGPRI11.PA.LCL>

I have two dual 2.4G Xeon processors (4 cpus). This is what I got as the = results of your
suggested query. I'm not too surprised because I don't know what I'm = looking at yet! My next step will=20
probably be to take one real world query and try and optimize that.=20

=
queries parallelized = 7 DML statements parallelized = 0 DDL statements parallelized = 0 DFO trees parallelized = 7 Parallel operations not downgraded = 7 Parallel operations downgraded to serial = 0 Parallel operations downgraded 75 to 99 pct = 0 Parallel operations downgraded 50 to 75 pct = 0 Parallel operations downgraded 25 to 50 pct = 0 Parallel operations downgraded 1 to 25 pct = 0

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of John Kanagaraj Sent: Tuesday, February 10, 2004 6:49 PM To: 'oracle-l_at_freelists.org'
Subject: RE: Implement Parallel Processing on DB Warehouse

Don,

As Jonathan pointed out, AUTOTRACE cannot be relied upon. Rather, I = would
look at V$SESSTAT from another session for the identified SID - this provides some additional details, especially about PQ. Specifically, = look
for Statistics (join V$STATNAME) 'where upper(name) like '%PARALLEL%'' - = you
will be gently surprised s'all I can say :) You also did not mention the number of CPUs you have (although I note that you have set parallel_threads_per_cpu). Be aware that although you did not set LARGE_POOL, this will automatically be derived.

And I have to disagree with Mladen here on the flushing bit - since this = is
a DW, I wouldn't mind flushing the shared pool, as I can understand why = you
did it. Of course, he did point out the syntax error!=20

PQ (in a controlled fashion) can be a boon in DWs, but I have seen it = really
bite in an OLTP environment.
John Kanagaraj
DB Soft Inc
Phone: 408-970-7002 (W)

Listen to great, commercial-free christian music 24x7x365 at http://www.klove.com

The opinions and facts contained in this message are entirely mine = and do not reflect those of my employer or customers **

>-----Original Message-----
>From: oracle-l-bounce_at_freelists.org=20
>[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Freeman, Donald
>Sent: Tuesday, February 10, 2004 1:18 PM
>To: oracle-l_at_freelists.org
>Subject: Implement Parallel Processing on DB Warehouse

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Received on Wed Feb 11 2004 - 09:17:55 CST