Re: Performance of query (fwd)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Edmund Dengler <edmundd(at)eSentire(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Performance of query (fwd)
Date: 2003-06-11 16:58:34
Message-ID: 19959.1055350714@sss.pgh.pa.us
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Edmund Dengler <edmundd(at)eSentire(dot)com> writes:
> Ok, tried it with a constant. No improvements. The estimator is still very
> high.

> where timestamp > '2003-06-11 9:22 EDT'::timestamp

> -> Index Scan using timestamp_idx on event (cost=0.00..557630.23 rows=237136 width=24) (actual time=0.22..16.58 rows=139 loops=1)
> Index Cond: ("timestamp" > ('2003-06-11 09:22:00'::timestamp without time zone)::timestamp with time zone)

It would probably help if you cast the constant to the same datatype
as the column is (which is evidently timestamp with time zone).
Coercions between timestamp and timestamptz are not considered
constants, because they depend on SET TIMEZONE.

regards, tom lane

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