Re: CPU cost of operators - Mailing list pgsql-performance

From Robert Haas
Subject Re: CPU cost of operators
Date
Msg-id 603c8f070909301314s125329a4p2e898a0e9f5f7979@mail.gmail.com
Whole thread Raw
In response to Re: CPU cost of operators  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: CPU cost of operators
Re: CPU cost of operators
List pgsql-performance
On Wed, Sep 30, 2009 at 4:13 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Wed, Sep 30, 2009 at 1:12 PM, Matthew Wakeling <matthew@flymine.org> wrote:
>>
>> Episode umpteen of the ongoing saga with my GiST indexes.
>>
>> For some reason, GiST uses loads of CPU. I have a query that runs entirely
>> out of cache, and it takes ages. This much I have tried to fix and failed so
>> far.
>>
>> What I would now like to do is to tell postgres about it, so that the
>> EXPLAINs are correct. Is there a way to tell Postgres that an operator has a
>> large CPU cost? I can tell it what the join selectivity is, but I can't find
>> anything about CPU cost.
>
> Not that I know of, but seems like it would be a reasonable extension.

Er, wait... if you set the 'COST' parameter for the backing function,
does that work?
.
...Robert

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