On 2016-06-03 12:31:58 -0400, Robert Haas wrote: > Now, what varies IME is how much total RAM there is in the system and > how frequently they write that data, as opposed to reading it. If > they are on a tightly RAM-constrained system, then this situation > won't arise because they won't be under the dirty background limit. > And if they aren't writing that much data then they'll be fine too. > But even putting all of that together I really don't see why you're > trying to suggest that this is some bizarre set of circumstances that > should only rarely happen in the real world.
I'm saying that if that happens constantly, you're better off adjusting shared_buffers, because you're likely already suffering from latency spikes and other issues. Optimizing for massive random write throughput in a system that's not configured appropriately, at the cost of well configured systems to suffer, doesn't seem like a good tradeoff to me. Note that other operating systems like windows and freebsd *alreaddy* write back much more aggressively (independent of this change). I seem to recall you yourself being quite passionately arguing that the linux behaviour around this is broken. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers