| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Ian Turner" <ian(dot)turner(at)deshaw(dot)com> |
| Cc: | pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: BUG #4974: Equivalent of "= ANY" and "BETWEEN" not observed by planner. |
| Date: | 2009-08-12 02:15:19 |
| Message-ID: | 2814.1250043319@sss.pgh.pa.us |
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| Lists: | pgsql-bugs |
"Ian Turner" <ian(dot)turner(at)deshaw(dot)com> writes:
> The following queries are equivalent, because there are no integers between
> 5 and 6 and because the BETWEEN operator contemplates a closed range.
> SELECT * FROM example WHERE pk IN (5,6);
> SELECT * FROM example WHERE pk BETWEEN 5 AND 6;
The planner intentionally does not do very many inferences that are as
datatype-dependent as this one would be. It doesn't fit into the system
design. For the most part the possible gain is not large anyway.
regards, tom lane
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