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Re: [HACKERS] psql nested queries with 2000+ records

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: coronach(at)hill-b-073(dot)resnet(dot)purdue(dot)edu (Coronach)
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] psql nested queries with 2000+ records
Date: 1998-03-20 17:24:05
Message-ID: 199803201724.MAA08299@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
> 
> I have noted with 2000+ records in a table (using a btree unique index on
> the primary key, btw) performance of a query takes 15+ minutes to respond.
> 
> The query is in the structure of this
> 
> select foo from bar where foo in (select foo from bar where bazzfoo like
> 'Word%');

Very strange.  15+ minutes?  Wow, that is terrible, even longer than a
sequential scan of the table.  Try EXPLAIN and tell us what it says in
the two cases.

> 
> Just reporting a possible bug..
> 
> With smaller amounts of records, responce time is within a few seconds.
> 
> Other information you might want:
> 
> postgres version: 6.3
> os: BSDI 3.1

Same OS here.
-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist(at)candle(dot)pha(dot)pa(dot)us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

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Subject: Re: [HACKERS] tables >2GB
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