| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Hannu Krosing <hannu(at)tm(dot)ee> |
| Cc: | Josh Berkus <josh(at)agliodbs(dot)com>, Dustin Sallings <dustin(at)spy(dot)net>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: inconsistent/weird index usage |
| Date: | 2004-10-02 23:44:21 |
| Message-ID: | 27189.1096760661@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
Hannu Krosing <hannu(at)tm(dot)ee> writes:
>> No. It's not fixed as of CVS tip either, although there was some talk
>> of doing something in time for 8.0.
> That's weird - my 7.4.2 databases did not consider (now()-'15
> min'::interval) to be a constant whereas 7.4.5 does (i.e. it does use
> index scan on index on datetime column)
The question isn't whether it can use it as an indexscan bound; the
question is whether it can derive an accurate rowcount estimate.
The issue is exactly that STABLE functions work for one but not the
other.
regards, tom lane
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