| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
| Cc: | "Guillaume Smet" <guillaume(dot)smet(at)gmail(dot)com>, "pgsql-performance" <pgsql-performance(at)postgresql(dot)org>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [HACKERS] Estimation problem with a LIKE clause containing a / |
| Date: | 2007-11-09 16:33:45 |
| Message-ID: | 11342.1194626025@sss.pgh.pa.us |
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| Lists: | pgsql-hackers pgsql-performance |
Gregory Stark <stark(at)enterprisedb(dot)com> writes:
> Could we not use the bogus range to calculate the histogram estimate
> but apply the LIKE pattern directly to the most-frequent-values
> instead of applying the bogus range? Or would that be too much code
> re-organization for now?
We have already done that for quite some time. It won't help
Guillaume's case anyhow: he's got no MCVs, presumably because the field
is unique.
regards, tom lane
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