Re: [PERFORM] BETWEEN optimizer problems with single-value range

From: "Merlin Moncure" <mmoncure(at)gmail(dot)com>
To: "Andreas Kretschmer" <akretschmer(at)spamfence(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org, "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>, "postgres hackers" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [PERFORM] BETWEEN optimizer problems with single-value range
Date: 2006-03-15 22:11:16
Message-ID: b42b73150603151411h293c4942v160960aaa8c9cd1e@mail.gmail.com
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On 3/15/06, Andreas Kretschmer <akretschmer(at)spamfence(dot)net> wrote:
> Merlin Moncure <mmoncure(at)gmail(dot)com> schrieb:
>
> > On 3/15/06, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
> > > Attached is a simplified example of a performance problem we have seen,
> > > with a workaround and a suggestion for enhancement (hence both the
> > > performance and hackers lists).
> >
> >
> > Hi Kevin. In postgres 8.2 you will be able to use the row-wise
>
> 8.2? AFAIK, Feature freeze in juni/juli this year...
> Release august/september.

yes, but I was addressing kevin's point about enhancing the server...

> > comparison for your query which should guarantee good worst case
> > performance without having to maintain two separate query forms. it
>
> Perhaps, a bitmap index scan (since 8.1) are useful for such querys.
> Thats why i asked which version.

I think you will find that reading a range of records from a table
ordered by an index utilizing the 8.2 comparison feature is much
faster than a bitmap index scan.

Merlin

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