Heikki Linnakangas <heikki.linnakan...@enterprisedb.com> writes: > Tom Lane wrote: >> Quite aside from that, the fixed size of shared memory makes this seem >> pretty impractical.
> Most state files are small. If one doesn't fit in the area reserved for > this, it's written to disk as usual. It's just an optimization. What evidence do you have for that assumption? And what's "small" anyway? I think setting the size parameter for this would be a frightfully difficult problem; the fact that average installations wouldn't use it doesn't make that any better for those who would. After our bad experiences with fixed-size FSM, I'm pretty wary of introducing new fixed-size structures that the user is expected to figure out how to size. > I'm a bit disappointed by the performance gains. I would've expected > more, given a decent battery-backed-up cache to buffer the WAL fsyncs. > But it looks like they're still causing the most overhead, even with a > battery-backed-up cache. If you can't demonstrate order-of-magnitude speedups, I think we shouldn't touch this. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers