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Re: Weird index or sort behaviour

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Matthew Wakeling <matthew(at)flymine(dot)org>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Weird index or sort behaviour
Date: 2009-08-18 16:49:37
Message-ID: 24785.1250614177@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-performance
Matthew Wakeling <matthew(at)flymine(dot)org> writes:
> Very clever. Yes, that is what is happening. I'm surprised that the system 
> doesn't buffer the inner side to avoid having to rescan each time, but 
> then I guess you would have problems if the buffer grew larger than 
> memory.

Well, it does consider adding a Materialize node for that purpose,
but in this case it evidently thought a sort was cheaper.

			regards, tom lane

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