Re: 8.x index insert performance - Mailing list pgsql-performance

From Merlin Moncure
Subject Re: 8.x index insert performance
Date
Msg-id 6EE64EF3AB31D5448D0007DD34EEB3417DD732@Herge.rcsinc.local
Whole thread Raw
In response to 8.x index insert performance  (Kelly Burkhart <kelly@tradebotsystems.com>)
Responses Re: 8.x index insert performance  (Greg Stark <gsstark@mit.edu>)
List 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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