Re: PQ_DISTRIBUTE Usage in NON Parallel Queries
- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Sun, 6 Feb 2005 16:49:56 -0000
Did the OL$HINTS table also have a noparallel
and noparallel_index hint ? If not, then the query
could go parallel, which would make a pq_distribute
hint relevant..
Alternatively, there are a few oddities in the 9.2.0.5
when it comes to parallel query that I have not been
able to reproduce in 9.2.0.4 and 9.2.0.6 (yet), so maybe
you've found a symptom of a generic parallel bug.
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/seminar.html
Public Appearances - schedule updated Jan 21st 2005
----- Original Message -----
From: "Larry Elkins" <elkinsl@xxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Saturday, February 05, 2005 1:41 AM
Subject: PQ_DISTRIBUTE Usage in NON Parallel Queries
Listers,
In what way does the PQ_DISTRIBUTE "hint" apply to non parallel queries? I
ran into a need to use a stored outline a while back. And the query does not
use parallelism. When capturing the desired plan in the OL$HINTS table for
the outline there is a PQ_DISTRIBUTE hint. The docs categorize it as a
parallel related hint, and I've had to use it a couple of times in the past
related to parallel queries for huge batch jobs (and yes, I tried tweaking
stats first ;-)).
This actually came up a couple of months ago, and I no longer have access to
the system or else I would dig into it a bit more, and even provide the SQL,
it's plan, and the data from OL$HINTS to the list. But no can do without
access to it. I just find it odd that the docs, and whatever else Oracle
puts out on Metalink, etc, that it is always referred to as being a parallel
related hint. Yet it appears in OL$HINTS for a SQL statement not using
parallelism.
Oh yeah, 9.2.0.5 EE. And I'm going to see if I can duplicate on 8i and 9i
here at home, but thought I would throw the question out to the list as
well.
Regards,
Larry G. Elkins
elkinsl@xxxxxxxxx
214.954.1781
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