Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers

On 01/08/2013 08:08 PM, Tom Lane wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> On Tue, Jan 8, 2013 at 7:17 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> ... And I don't especially like the idea of trying to
>>> make it depend directly on the box's physical RAM, for the same
>>> practical reasons Robert mentioned.
>> For the record, I don't believe those problems would be particularly
>> hard to solve.
> Well, the problem of "find out the box's physical RAM" is doubtless
> solvable if we're willing to put enough sweat and tears into it, but
> I'm dubious that it's worth the trouble. The harder part is how to know
> if the box is supposed to be dedicated to the database. Bear in mind
> that the starting point of this debate was the idea that we're talking
> about an inexperienced DBA who doesn't know about any configuration knob
> we might provide for the purpose.
>
> I'd prefer to go with a default that's predictable and not totally
> foolish --- and some multiple of shared_buffers seems like it'd fit the
> bill.

+1. That seems to be by far the biggest bang for the buck. Anything else
will surely involve a lot more code for not much more benefit.

cheers

andrew