From: Scott Marlowe <scott.marlowe@gmail.com>
To: Vladimir Sitnikov <sitnikov.vladimir@gmail.com>
Cc: Tomas Vondra <tv@fuzzy.cz>
Cc: Andrus <kobruleht2@hot.ee>
Cc: pgsql-performance@postgresql.org
Subject: Re: Using index for IS NULL query
Date: Tue, 11 Nov 2008 16:34:42 -0700
Message-ID: <dcc563d10811111534x3957273aw8365cb497cc0c91c@mail.gmail.com> (raw)
In-Reply-To: <1d709ecc0811111500i3c63e345qfa3be90264629256@mail.gmail.com>
References: <gfcprb$m40$1@news.hub.org>
<4919F2C6.4000303@fuzzy.cz>
<1d709ecc0811111500i3c63e345qfa3be90264629256@mail.gmail.com>
On Tue, Nov 11, 2008 at 4:00 PM, Vladimir Sitnikov
<sitnikov.vladimir@gmail.com> wrote:
>
>> Yes, NULL values are not stored in the index, but you may create
>> functional index on
>
> Are you sure NULL values are not stored? btree, gist and bitmap index and
> search for NULL values.
It's not that they're not stored, it's that before 8.3 pg didn't know
how to compare to them I believe. The standard trick was to create a
partial index with "where x is null" on the table / column. 8.3 knows
how to compare them and doesn't need the partial index.
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To: pgsql-performance@postgresql.org
Cc: scott.marlowe@gmail.com, sitnikov.vladimir@gmail.com, tv@fuzzy.cz, kobruleht2@hot.ee
Subject: Re: Using index for IS NULL query
In-Reply-To: <dcc563d10811111534x3957273aw8365cb497cc0c91c@mail.gmail.com>
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