On Wed, Apr 16, 2014 at 1:44 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Merlin Moncure <mmonc...@gmail.com> writes: >> Anyways, I'm still curious if you can post similar numbers basing the >> throttling on gross allocation counts instead of time. Meaning: some >> number of buffer allocations has to have occurred before you consider >> eviction. Besides being faster I think it's a better implementation: >> an intermittently loaded server will give more consistent behavior. > > Yeah --- I think wall-clock-based throttling is fundamentally the wrong > thing anyway. Are we going to start needing a CPU speed measurement to > tune the algorithm with? Not the place to be going. But driving it off > the number of allocations that've been done could be sensible. (OTOH, > that means you need a central counter, which itself would be a > bottleneck.)
sure -- note we already track that in BufferStrategyControl (everything in buffer allocation is already centrally managed essentially). /* * Statistics. These counters should be wide enough that they can't * overflow during a single bgwriter cycle. */ uint32 completePasses; /* Complete cycles of the clock sweep */ uint32 numBufferAllocs; /* Buffers allocated since last reset */ merlin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers