Re: CLOG contention

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> So, what do we do about this? The obvious answer is "increase
> NUM_CLOG_BUFFERS", and I'm not sure that's a bad idea.

As you say, that's likely to hurt people running in small shared
memory. I too have thought about merging the SLRU areas into the main
shared buffer arena, and likewise have concluded that it is likely to
be way more painful than it's worth. What I think might be an
appropriate compromise is something similar to what we did for
autotuning wal_buffers: use a fixed percentage of shared_buffers, with
some minimum and maximum limits to ensure sanity. But picking the
appropriate percentage would take a bit of research.

regards, tom lane