Message-ID: <54EEFDA1.7020609@tbz-pariv.de>
Date: Thu, 26 Feb 2015 12:04:01 +0100
From: "Sven R. Kunze" <srkunze@tbz-pariv.de>
Organization: TBZ-PARIV GmbH
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To: Josh Berkus <josh@agliodbs.com>, Tom Lane <tgl@sss.pgh.pa.us>
CC: pgsql-performance@postgresql.org
Subject: Re: Reverse Key Index
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On 25.02.2015 23:31, Josh Berkus wrote:
> On 02/14/2015 10:35 AM, Sven R. Kunze wrote:
>> Thanks for the immediate reply.
>>
>> I understand the use case is quite limited.
>>
>> On the other hand, I see potential when it comes to applications which
>> use PostgreSQL. There, programmers would have to change a lot of code to
>> tweak existing (and more importantly working) queries to hash/reverse an
>> id column first. Using ORMs would make this change even more painful and
>> maybe even impossible.
>>
>> When reading
>> https://richardfoote.wordpress.com/2008/01/14/introduction-to-reverse-ke=
y-indexes-part-i/
>> carefully, it also seems to work with index scan partially in case of
>> equality comparisons.
> Seems like a good use for SP-GiST.  Go for it!
>

I just thought about btree indexes here mainly because they well-known=20
and well-used in ORM frameworks. Considering the documentation and=20
third-party posts on GiST and btree_gist, at least to me, it seems as if=20
people would not want to use that for integers; which in turn is the=20
main use-case scenario for reverse key indexes.

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Sven R. Kunze
TBZ-PARIV GmbH, Bernsdorfer Str. 210-212, 09126 Chemnitz
Tel: +49 (0)371 33714721, Fax: +49 (0)371 5347920
e-mail: srkunze@tbz-pariv.de
web: www.tbz-pariv.de

Gesch=C3=A4ftsf=C3=BChrer: Dr. Reiner Wohlgemuth
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Registergericht: Chemnitz HRB 8543


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