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Re: 8.x index insert performance

From: "Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com>
To: "Scott Marlowe" <smarlowe(at)g2switchworks(dot)com>
Cc: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: 8.x index insert performance
Date: 2005-10-31 21:10:57
Message-ID: 6EE64EF3AB31D5448D0007DD34EEB3417DD732@Herge.rcsinc.local (view raw or flat)
Thread:
Lists: pgsql-performance
> select * from sometable where somefield IS NULL won't work because IS
is
> not a nomally indexible operator.

Ah, I didn't know that.  So there is no real reason not to exclude null
values from all your indexes :).  Reading Tom's recent comments
everything is clear now.

Instead of using your two index approach I prefer to:
create function nullidx(anyelement) returns boolean as $$ select $1 is
null; $$ language
sql immutable;

create index on t(nullidx(f)); -- etc

Merlin

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Subject: Re: 8.x index insert performance
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