Re: Working on huge RAM based datasets

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Merlin Moncure
Тема
Re: Working on huge RAM based datasets
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6EE64EF3AB31D5448D0007DD34EEB34101AEC9@Herge.rcsinc.local
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Re: Working on huge RAM based datasets Christopher Browne <cbbrowne@acm.org>
Re: Working on huge RAM based datasets Rod Taylor <pg@rbt.ca>
Re: Working on huge RAM based datasets Josh Berkus <josh@agliodbs.com>
Re: Working on huge RAM based datasets Jan Wieck <JanWieck@Yahoo.com>
Jan wrote:
> > The disk cache on most operating systems is optimized.  Plus,
keeping
> > shared buffers low gives you more room to bump up the sort memory,
which
> > will make your big queries run faster.
> 
> Plus, the situation will change dramatically with 7.5 where the disk
> cache will have less information than the PG shared buffers, which
will
> become sequential scan resistant and will know that a block was pulled
> in on behalf of vacuum and not because the regular database access
> pattern required it.

Hm. In my experience the different between data cached between shared
buffers and the O/S is not very much...both are fast.  However, I almost
always see dramatic performance speedups for bumping up work mem.  Are
you suggesting that it will be advantageous to bump up shared buffers?

Merlin


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