RE: Parallel query on when it's not supposed to be (?)

From: Bobak, Mark <Mark.Bobak_at_il.proquest.com>
Date: Wed, 15 Sep 2004 01:43:20 -0400
Message-ID: <4C9B6FDA0B06FE4DAF5918BBF0AD82CF09EFEB5B@bosmail00.bos.il.pqe>

Gee, I guess I should have read Mladen's message before posting! He already pretty much covered it!

-----Original Message-----

From:	oracle-l-bounce_at_freelists.org on behalf of Mladen Gogala
Sent:	Wed 9/15/2004 12:05 AM
To:	mrichard_at_transurban.com.au; oracle-l
Cc:=09
Subject:	Re: Parallel query on when it's not supposed to be (?)

On 09/14/2004 10:03:10 PM, Mark Richard wrote:

>=20
>=20
>=20
>=20

> I just wanted to pose a question to anyone on the list (particular the =
wait
> event guru's like Cary)...

Event guru? That's what Cary is? Hmmm, not exactly the expression that I'd use.

>=20
> Eliminating parallel query because you are seeing waits for it sounds =
to me
> a little like tuning the BCHR. I can't help but wonder if waiting for =
a
> parallel query is still the quickest way to get things done? Would =
killing
> the parallel query effectively move the waits to another category =
without
> achieving any real gain?

If the instance is OLTP with several hundreds of concurrent users, you = definitely
don't want PQ utilized by users, on regular basis, because it would = quickly=20
drain your machine resources. If a full table scan somehow makes it into = production,
and it happens even to the best of us, then you want to minimize the = damage and
not resolve it by devoting enormous resources to it, thus starving = everybody=20
else of CPU power. PQ is not a magic potion thad druid Getafix used to = cook
(I apologize to my American friends who have never heard of Asterix and = Obelix)
to increase power of the tiny Gaul warrior, PQ is a tool that has its = place,
primarily in the batch and DW systems. Enabling PQ on a busy OLTP = instance is
something that can be compared to another French comic, namely Gaston. = There are
many French speaking people on this list, they may explain to you = everything
about Gaston Lagaffe.=20
--=20
Mladen Gogala
Oracle DBA

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Received on Wed Sep 15 2004 - 00:38:55 CDT