From: | Bryce Nesbitt <bryce2(at)obviously(dot)com> |
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To: | sql pgsql <pgsql-sql(at)postgresql(dot)org> |
Subject: | Re: index compatible date_trunc in postgres? |
Date: | 2008-12-19 18:15:37 |
Message-ID: | 494BE4C9.7020607@obviously.com |
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Lists: | pgsql-sql |
Tom Lane wrote:
> Why are you worrying? The old method surely didn't get indexed either.
Continuous improvement?
Since there already IS an index available, I figure I might as well use
it, especially since this DB had real performance issues. The table
itself is medium sized in our world, at 647596 rows.
Scott Marlowe wrote:
> You can create an index on date_trunc (on timestamp without timezone,
> but not on timestamp with timezone since it's not immutable)
That could work...
create index brycetest5 on contexts (date_trunc('month',publication_date));
(13 MB index, same size as the index on the non-truncated date).
Unfortunately complains about immutability:
create index brycetest5 on contexts (to_char(publication_date,'YYYY-MM'));
But in this case I think I'll rewrite the query into a range, and stick
with the present index.
Thanks for your help.
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