Skip site navigation (1) Skip section navigation (2)

Re: Bad plan choice nestloop vs. hashjoin

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Kenneth Marshall <ktm(at)rice(dot)edu>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Bad plan choice nestloop vs. hashjoin
Date: 2010-01-16 00:27:27
Message-ID: 24460.1263601647@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-performance
Kenneth Marshall <ktm(at)rice(dot)edu> writes:
> We have just upgraded our monitoring server software and
> now the following query for graphing the data performs
> abysmally with the default settings. Here is the results
> of the EXPLAIN ANALYZE run with nestloops enabled:

That plan seems a bit wacko --- I don't see a reason for it to be using
an indexscan on items ii.  Can you extract a self-contained test case?

			regards, tom lane

In response to

pgsql-performance by date

Next:From: Eduardo PiombinoDate: 2010-01-16 00:47:35
Subject: Re: a heavy duty operation on an "unused" table kills my server
Previous:From: Kenneth MarshallDate: 2010-01-16 00:14:40
Subject: Re: Bad plan choice nestloop vs. hashjoin

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group