>> On Tue, 07 Aug 2001, Tom Lane wrote:
>> I'm on 7.1
>> (PostgreSQL 7.1.2 on i686-pc-linux-gnu, compiled by GCC 2.95.4)
> Okay ... [ looks at code ... ] oh, I see the problem. The pattern-match
> selectivity code doesn't try to deal with "lower(foo) LIKE ...":
> /*
> * If expression is not var op constant for
> * a simple var of a real relation (no subqueries, for now),
> * then punt and return a default estimate.
> */
> This could probably be improved, but I don't have time to think
> about it now. In the meantime you could try knocking
> DEFAULT_MATCH_SEL down a little bit. (It's already been reduced to
> 0.005 in current sources, in fact.) See
> src/backend/utils/adt/selfuncs.c.
Has this improved any since Aug. ? I tried to look in the current CVS,
but I don't know where this code would be. I did a quick find and
couldn't locate the comment shown above anywhere.
(I've returned to my original project, and tried reducing
DEFAULT_MATCH_SEL in 7.1.3 to 0.005 (it was 0.01 in the current cygwin
source); this didn't help so I'm going to use lowercase only entries
in my tables for now so I don't have to index lower(item)).
Nick
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