Re: Time to up bgwriter_lru_maxpages?

On 2/2/17 2:47 PM, Robert Haas wrote:
> On Wed, Feb 1, 2017 at 9:47 PM, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> wrote:
>> Before doing that the first thing to look at would be why the limit is
>> currently INT_MAX / 2 instead of INT_MAX.
>
> Generally the rationale for GUCs with limits of that sort is that
> there is or might be code someplace that multiplies the value by 2 and
> expects the result not to overflow.
>
> I expect that increasing the maximum value of shared_buffers beyond
> what can be stored by an integer could have a noticeable distributed
> performance cost for the entire system. It might be a pretty small
> cost, but then again maybe not; for example, BufferDesc's buf_id
> member would have to get wider, and probably the freeNext member, too.
> Andres already did unspeakable things to make a BufferDesc fit into
> one cache line for performance reasons, so that wouldn't be great
> news.
>
> Anyway, I committed the patch posted here. Or the important line out
> of the two, anyway. :-)

It seems that this submission should be marked as "Committed" with
Robert as the committer. Am I missing something?

--
-David
david(at)pgmasters(dot)net