Re: left outer join taking too long?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Johnson, Shaunn" <SJohnson6(at)bcbsm(dot)com>
Cc: "pg-general (E-mail)" <pgsql-general(at)postgresql(dot)org>
Subject: Re: left outer join taking too long?
Date: 2003-05-02 21:16:57
Message-ID: 2635.1051910217@sss.pgh.pa.us
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"Johnson, Shaunn" <SJohnson6(at)bcbsm(dot)com> writes:
> Merge Join (cost=1081799.72..1088792.93 rows=1518781 width=237)
> -> Index Scan using t_mbr_ben_spans_i on t_mbr_ben_spans b
> (cost=0.00..3053.66 rows=51333 width=30)
> -> Sort (cost=1081799.72..1081799.72 rows=1518781 width=207)
> -> Seq Scan on mbr a (cost=0.00..73602.81 rows=1518781 width=207)

Increasing sort_mem would make that cost estimate drop. What effects
it'd have on the actual runtime is harder to say; but I never trust
EXPLAIN's estimates very much ;-)

regards, tom lane

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