On Apr 16, 2010, at 4:56 PM, Robert Haas wrote:
> From reading this and other threads, I think I generally understand
> that the perils of setting shared_buffers too high: memory is needed
> for other things, like work_mem, a problem which is exacerbated by the
> fact that there is some double buffering going on. Also, if the
> buffer cache gets too large, checkpoints can involve writing out
> enormous amounts of dirty data, which can be bad.
I've also seen large shared buffer settings perform poorly outside of IO issues, presumably due to some kind of
internallock contention. I tried running 8.3 with 24G for a while, but dropped it back down to our default of 8G after
noticingsome performance problems. Unfortunately I don't remember the exact details, let alone having a repeatable test
case.
--
Jim C. Nasby, Database Architect jim@nasby.net
512.569.9461 (cell) http://jim.nasby.net
