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Re: Parallel querying with partitioned table

From: <yong321_at_yahoo.com>
Date: Sun, 24 Jun 2007 07:37:25 -0700
Message-ID: <1182695845.447239.298400@a26g2000pre.googlegroups.com>


On Jun 24, 2:25 pm, "Jonathan Lewis" <jonat..._at_jlcomp.demon.co.uk> wrote:
> <yong..._at_yahoo.com> wrote in message
>
> news:1182660308.546819.120970_at_z28g2000prd.googlegroups.com...
>
>
>
> > [I caught you top-post, Jonathan!]
>
> "Top-posting" wasn't a sin when I started using the newsgroups,
> and it's more appropriate for email - so sometimes I forget.
>
>
>
> > Would setting parallel_adaptive_multi_user to false get us closer to
> > the M=N goal?
>
> No.
>
> > Documentation says there's no way to tell Oracle to use
> > block range granules instead of partition granules, or the other way.
> > Any comment?
>
> Where did you find this comment in the documentation, I hadn't
> come across it.
>
> For some special cases the pq_distribute() hint - for parallel
> joins - will have an effect.
>
> > Unrelated. Why is the much touted parallel_automatic_tuning deprecated
> > in 10g? Is it against Oracle's trend of increasing auto-tuning, or
> > it's because all the implied changes (message size doubled etc)
> > already default?
>
> I hadn't realised that parallel_automatic_tuning was "much
> touted". Most of the comments I've heard about it have been
> negative - mostly because it sets parallel_adaptive_multi_user
> to true when you enable it.
>
> Your guess is as good as mine. The feature may be deprecated
> because Oracle wants to leave it 'always on' in future.
>
> > Yong Huang
>
> --
> Regards
>
> Jonathan Lewishttp://jonathanlewis.wordpress.com
>
> Author: Cost Based Oracle: Fundamentalshttp://www.jlcomp.demon.co.uk/cbo_book/ind_book.html
>
> The Co-operative Oracle Users' FAQhttp://www.jlcomp.demon.co.uk/faq/ind_faq.html

Data warehousing guide
http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14223/usingpe.htm says "There is no way you can enforce a specific granule strategy as Oracle Database makes this decision internally."

pq_distribute hint at least has some control on whether mapping to partitions or not. That's good. Thanks.

I'm under the impression that until 10g, Oracle has been recommending parallel_automatic_tuning. (Forget my comment "much touted".) I didn't know parallel_adaptive_multi_user was a bad thing.

Yong Huang Received on Sun Jun 24 2007 - 09:37:25 CDT

Original text of this message

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