Re: GiST, caching, and consistency - Mailing list pgsql-performance

From Greg Stark
Subject Re: GiST, caching, and consistency
Date
Msg-id 407d949e0908041627r121b228n1ccd834a66c8fc13@mail.gmail.com
Whole thread Raw
In response to Re: GiST, caching, and consistency  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: GiST, caching, and consistency
List pgsql-performance
On Tue, Aug 4, 2009 at 11:56 PM, Robert Haas<robertmhaas@gmail.com> wrote:
> Beats me.  It looks like the first few queries are pulling stuff into
> cache, and then after that it settles down, but I'm not sure why it
> takes 5 repetitions to do that.  Is the plan changing?

Yeah, we're just guessing without the explain analyze output.

But as long as we're guessing, perhaps it's doing a sequential scan on
one of the tables and each query is reading in new parts of the table
until the whole table is in cache. Is this a machine with lots of RAM
but a small setting for shared_buffers?


--
greg
http://mit.edu/~gsstark/resume.pdf

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