Re: Indexes and outer join?

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От Tom Lane
Тема Re: Indexes and outer join?
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Msg-id 3915.1015254810@sss.pgh.pa.us
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Ответ на Indexes and outer join?  (Heni Lolov <hal_bg@yahoo.com>)
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Heni Lolov <hal_bg@yahoo.com> writes:
> explain select *
> from tyc_glup
> where de>0 and de<1000000 and ra<100000 and ra>0;

> NOTICE:  QUERY PLAN:

> Merge Join  (cost=42975.66..44050.21 rows=34159 width=50)
>   ->  Sort  (cost=108.53..108.53 rows=26 width=14)
>         ->  Index Scan using tycho_drm on tycho  (cost=0.00..107.90 rows=26
> width=14)
>   ->  Sort  (cost=42867.14..42867.14 rows=258997 width=36)
>         ->  Seq Scan on sao  (cost=0.00..4609.97 rows=258997 width=36)

Hmm.  This plan doesn't make a lot of sense to me; with so few rows
coming out of tycho, I'd have expected the thing to pick a nestloop.
Do you have enable_nestloop turned off?  What plan do you get for this
query if you set enable_mergejoin to off?

Also, what PG version is this?

            regards, tom lane

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