| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "scott(dot)marlowe" <scott(dot)marlowe(at)ihs(dot)com> |
| Cc: | Joseph Shraibman <jks(at)selectacast(dot)net>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: like performance w/o wildcards. |
| Date: | 2003-08-05 15:22:12 |
| Message-ID: | 22747.1060096932@sss.pgh.pa.us |
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| Lists: | pgsql-general |
"scott.marlowe" <scott(dot)marlowe(at)ihs(dot)com> writes:
>>> It does ... if the index-conversion optimization is enabled at all.
>>
>> Sorry, what is 'index-conversion optimization' and when is it enabled?
> I don't know what that is either. Tom?
Sorry, I just meant the code that tries to extract indexable conditions
from a LIKE clause. With a fixed-prefix pattern, eg "x LIKE 'foo%'",
you get a range condition like "x >= 'foo' AND x < 'fop'". For a
completely fixed pattern this degenerates to "x = 'foo'". The whole
thing turns off in non-C locales though.
regards, tom lane
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