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Thread: index support is NULL

index support is NULL

From
Teodor Sigaev
Date:
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@sigaev.ru
                                                    WWW: http://www.sigaev.ru/

Re: index support is NULL

From
Bruce Momjian
Date:
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@sigaev.ru
>                                                     WWW: http://www.sigaev.ru/
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Have you searched our list archives?
>
>                http://archives.postgresql.org

--
  Bruce Momjian  <bruce@momjian.us>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

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

Re: index support is NULL

From
Tom Lane
Date:
Teodor Sigaev <teodor@sigaev.ru> writes:
> http://www.sigaev.ru/misc/indexnulls-0.8.gz

Applied with revisions (except I didn't touch the gist code, figuring
you probably understand that better than me).

            regards, tom lane