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Re: index support is NULL

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Teodor Sigaev <teodor(at)sigaev(dot)ru>
Cc: Patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: index support is NULL
Date: 2007-04-03 01:16:51
Message-ID: 200704030116.l331Gp110500@momjian.us (view raw or flat)
Thread:
Lists: pgsql-patches
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.

---------------------------------------------------------------------------


Teodor Sigaev wrote:
> http://www.sigaev.ru/misc/indexnulls-0.8.gz
> 
> Initially patch was developed by Martijn van Oosterhout. But it's reworked  and 
> support of searching NULLS to GiST too. Patch adds new column named amsearchnull 
> to pg_am. To recognize IS NULL clause ScanKey->sk_flags contains (SK_ISNULL & 
> SK_INDEXFINDNULL) and ScanKey->sk_strategy sets to InvalidStrategy. IS NOT NULL 
> isn't supported.
> 
> The patch was already suggested to community 
> (http://archives.postgresql.org/pgsql-patches/2006-12/msg00019.php
> and http://archives.postgresql.org/pgsql-hackers/2007-02/msg01162.php), but the 
> single objection was:
> http://archives.postgresql.org/pgsql-patches/2006-12/msg00028.php
> 
> Objection was about representing IS [NOT] NULL clause in SkanKey structure, 
> because it required to set strategy to BTEqualStrategyNumber, and Tom doubted 
> about needing of such support.
> 
> Now ScanKey->sk_strategy = InvalidStrategy and btree code transforms it to 
> BTEqualStrategyNumber in _bt_preprocess_keys(), btcostestimate knows that fact too.
> 
> GiST doesn't need to transform strategy - it looks at SK_INDEXFINDNULL only.
> 
> -- 
> Teodor Sigaev                                   E-mail: teodor(at)sigaev(dot)ru
>                                                     WWW: http://www.sigaev.ru/
> 
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-- 
  Bruce Momjian  <bruce(at)momjian(dot)us>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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