Re: Cluster vs. non-cluster query planning - Mailing list pgsql-performance

From Tom Lane
Subject Re: Cluster vs. non-cluster query planning
Date
Msg-id 20934.1146526502@sss.pgh.pa.us
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In response to Re: Cluster vs. non-cluster query planning  (Nolan Cafferky <Nolan.Cafferky@rbsinteractive.com>)
Responses Re: Cluster vs. non-cluster query planning  (Nolan Cafferky <Nolan.Cafferky@rbsinteractive.com>)
Re: Cluster vs. non-cluster query planning  ("Jim C. Nasby" <jnasby@pervasive.com>)
List pgsql-performance
Nolan Cafferky <Nolan.Cafferky@rbsinteractive.com> writes:
> But, I'm guessing that random_page_cost = 1 is not a realistic value.

Well, that depends.  If all your data can be expected to fit in memory
then it is a realistic value.  (If not, you should be real careful not
to make performance decisions on the basis of test cases that *do* fit
in RAM...)

In any case, if I recall your numbers correctly you shouldn't need to
drop it nearly that far to get the thing to make the right choice.
A lot of people run with random_page_cost set to 2 or so.

            regards, tom lane

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