Re: Partial Index Usage Performance Question

From: digory <digory_at_gmx.net>
Date: Tue, 14 Oct 2008 08:33:00 -0700 (PDT)
Message-ID: <427edf6d-b3a3-47e1-beac-24754ac4a619@i24g2000prf.googlegroups.com>


> > SELECT * FROM T WHERE a = ? AND b = ? AND c > t0
>
> > for some constant date t0, which is known to be older than any value
> > of c in T.
>
> So if t0 is older than any value in the table your query returns no
> rows, thus it could return MUCH faster than the query which eliminates
> c as a predicate.

That's not right. If t0 is older than any values of c, the condition c
> t0 holds for all rows in T, so the condition is actually redundant.
Received on Tue Oct 14 2008 - 10:33:00 CDT

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