Re: Caching (was Re: choosing the right platform)

How can we solve the problem of cache trashing when scanning large
tables?

Tom Lane wrote:
> 
> Jean-Luc Lachance <jllachan@nsd.ca> writes:
> > Shouldn't there be a way to lock some tables in PG cache?
> 
> In my opinion, no.  I do not think a manual locking feature could
> possibly be used effectively.  It could very easily be abused to
> decrease net performance, though :-(
> 
> It does seem that a smarter buffer management algorithm would be a good
> idea, but past experiments have failed to show any measurable benefit.
> Perhaps those experiments were testing the wrong conditions.  I'd still
> be happy to see LRU(k) or some such method put in, if someone can prove
> that it actually does anything useful for us.  (As best I recall, I only
> tested LRU-2 with pgbench.  Perhaps Josh's benchmarking project will
> offer a wider variety of interesting scenarios.)
> 
>                         regards, tom lane
> 
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