Sam Mason <sam@samason.me.uk> wrote:
> On Sun, Jul 19, 2009 at 11:15:39AM +0100, Pedro Doria Meunier wrote:
> > I have a table ~18M rows with a 'timestamp with time zone' column. It's
> > indexed thus:
> >
> > CREATE INDEX my_table_timestamp_idx
> > ON my_table
> > USING btree
> > (zulu_timestamp);
>
> Based on your query, I think you want a multi-column index---probably on
> (id,zulu_timestamp).
>
> The problem with just having an index on either column is that it's
> difficult to combine them and PG hence just thinks that it will be
Since 8.1 PG can do an bitmap index scan using both indexes...
Andreas
--
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