From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | Andy Colson <andy(at)squeakycode(dot)net> |
Cc: | pgsql <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: cannot get stable function to use index |
Date: | 2015-12-30 18:35:47 |
Message-ID: | 20564.1451500547@sss.pgh.pa.us |
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Lists: | pgsql-general |
Andy Colson <andy(at)squeakycode(dot)net> writes:
> No, that's not right, the table was empty. I rebuilt the table as it
> was before, here are all three queries again:
Ah, thanks for the more solid data.
> -> Bitmap Index Scan on search_key (cost=0.00..63623.00 rows=1 width=0) (actual time=4.996..4.996 rows=1 loops=1)
> Index Cond: (search_vec @@ to_tsquery('213 & E & 13 & ST & N:*'::text))
> -> Bitmap Index Scan on search_key (cost=0.00..23.00 rows=1 width=0) (actual time=4.057..4.057 rows=1 loops=1)
> Index Cond: (search_vec @@ to_tsquery('213 & E & 13 & ST & N'::text))
This says there's only about a 25% runtime penalty for the partial match,
at least on your example, compared to the planner's estimate of 2700x
penalty :-(. Definitely need to fix that.
regards, tom lane
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