Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers - Mailing list pgsql-hackers

From Tom Lane
Subject Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers
Date
Msg-id 28745.1399415312@sss.pgh.pa.us
Whole thread Raw
In response to Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> I basically think the auto-tuning we've installed for
> effective_cache_size is stupid.  Most people are going to run with
> only a few GB of shared_buffers, so setting effective_cache_size to a
> small multiple of that isn't going to make many more people happy than
> just raising the value - say from the current default of 128MB to, oh,
> 4GB - especially because in my experience queries aren't very
> sensitive to the exact value; it just has to not be way too small.  I
> bet the number of PostgreSQL users who would be made happy by a much
> higher hard-coded default is not too different from the number that
> will be made happy by the (completely unprincipled) auto-tuning.

There is a lot to be said for that argument, especially considering
that we're not even really happy with the auto-tuning mechanism,
never mind the behavior it's trying to implement.
        regards, tom lane



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