Re: Strange issue with GiST index scan taking far too long

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc: Mark Cave-Ayland <mark(dot)cave-ayland(at)siriusit(dot)co(dot)uk>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Strange issue with GiST index scan taking far too long
Date: 2008-06-09 17:25:14
Message-ID: 21579.1213032314@sss.pgh.pa.us
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Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> On Mon, 2008-06-09 at 11:49 -0400, Tom Lane wrote:
>> Is the value you are fetching from the geography table large enough to
>> be toasted? I'm thinking you might be looking at the cost of repeated
>> de-toastings.

> So you are saying it is de-toasted 32880 times, in this case? If not,
> where are the repeated de-toastings happening?

Inside the index support functions. I'm thinking we could fix this by
forcibly detoasting values passed as index scan keys, but it's not quite
clear where's the best place to do that.

regards, tom lane

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