Re: clog_buffers to 64 in 8.3?

Josh Berkus <josh(at)agliodbs(dot)com> writes:
> Tom,
>> I don't actually think that what Jignesh is testing is a particularly
>> realistic scenario, and so I object to making performance decisions on
>> the strength of that one measurement.

> What do you mean by "not realistic"? What would be a realistic scenario?

The difference between maxing out at 1200 sessions and 1300 sessions
doesn't excite me a lot --- in most environments you'd be well advised
to use many fewer backends and a connection pooler. But in any case
the main point is that this is *one* benchmark on *one* platform. Does
anyone outside Sun even know what the benchmark is, beyond the fact that
it's running a whole lot of sessions?

Also, you should not imagine that boosting NUM_CLOG_BUFFERS has zero
cost. The linear searches used in slru.c start to look pretty
questionable if we want more than a couple dozen buffers. I find it
entirely likely that simply changing the constant would be a net loss
on many workloads.

regards, tom lane