Re: AllocSetReset improvement

Your patch has been added to the PostgreSQL unapplied patches list at:

    http://momjian.postgresql.org/cgi-bin/pgpatches

It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.

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a_ogawa wrote:
>
> Tom Lane <tgl@sss.pgh.pa.us> writes:
> > a_ogawa <a_ogawa@hi-ho.ne.jp> writes:
> > > It is a reasonable idea. However, the majority part of MemSet was not
> > > able to be avoided by this idea. Because the per-tuple contexts are used
> > > at the early stage of executor.
> >
> > Drat.  Well, what about changing that?  We could introduce additional
> > contexts or change the startup behavior so that the ones that are
> > frequently reset don't have any data in them unless you are working
> > with pass-by-ref values inside the inner loop.
>
> That might be possible. However, I think that we should change only
> aset.c about this article.
> I thought further: We can check whether context was used from the last
> reset even when blocks list is not empty. Please see attached patch.
>
> The effect of the patch that I measured is as follows:
>
> o Execution time that executed the SQL ten times.
> (1)Linux(CPU: Pentium III, Compiler option: -O2)
>  - original: 24.960s
>  - patched : 23.114s
>
> (2)Linux(CPU: Pentium 4, Compiler option: -O2)
>  - original: 8.730s
>  - patched : 7.962s
>
> (3)Solaris(CPU: Ultra SPARC III, Compiler option: -O2)
>  - original: 37.0s
>  - patched : 33.7s
>
> regards,
>
> ---
> Atsushi Ogawa

[ Attachment, skipping... ]

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