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

On 7 May 2014 15:07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
>> I think I'm arguing myself towards using a BufferAccessStrategy of
>> BAS_BULKREAD for large IndexScans, BitMapIndexScans and
>> BitMapHeapScans.
>
> As soon as you've got some hard evidence to present in favor of such
> changes, we can discuss it.  I've got other things to do besides
> hypothesize.

Now we have a theory to test, I'll write a patch and we can collect
evidence for, or against.

> In the meantime, it seems like there is an emerging consensus that nobody
> much likes the existing auto-tuning behavior for effective_cache_size,
> and that we should revert that in favor of just increasing the fixed
> default value significantly.  I see no problem with a value of say 4GB;
> that's very unlikely to be worse than the pre-9.4 default (128MB) on any
> modern machine.
>
> Votes for or against?

+1 for fixed 4GB and remove the auto-tuning code.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services