Re: merge join killing performance - Mailing list pgsql-performance

From Matthew Wakeling
Subject Re: merge join killing performance
Date
Msg-id alpine.DEB.2.00.1005182254110.1867@aragorn.flymine.org
Whole thread Raw
In response to merge join killing performance  (Scott Marlowe <scott.marlowe@gmail.com>)
Responses Re: merge join killing performance  (Scott Marlowe <scott.marlowe@gmail.com>)
Re: merge join killing performance  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
On Tue, 18 May 2010, Scott Marlowe wrote:
> Aggregate  (cost=902.41..902.42 rows=1 width=4)
>   ->  Merge Join  (cost=869.97..902.40 rows=1 width=4)
>         Merge Cond: (f.eid = ev.eid)
>         ->  Index Scan using files_eid_idx on files f
> (cost=0.00..157830.39 rows=3769434 width=8)

Okay, that's weird. How is the cost of the merge join only 902, when the
cost of one of the branches 157830, when there is no LIMIT?

Are the statistics up to date?

Matthew

--
 As you approach the airport, you see a sign saying "Beware - low
 flying airplanes". There's not a lot you can do about that. Take
 your hat off?                                  -- Michael Flanders

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