On 2014-10-13 11:18:26 -0400, Bruce Momjian wrote: > On Mon, Oct 13, 2014 at 04:19:39PM +0200, Andres Freund wrote: > > On 2014-10-13 10:15:29 -0400, Robert Haas wrote: > > > On Sun, Oct 12, 2014 at 5:36 AM, Andres Freund <and...@2ndquadrant.com> > > > wrote: > > > > IIRC, as pointed out above, it's primarily based on a misunderstanding > > > > about when mmap is used for in dsm. I.e. that it's essentially just a > > > > fallback/toy implementation and that posix or sysv should rather be > > > > used. > > > > > > Perhaps, but I still see no reason not to apply it. It may not help > > > many people, but it won't hurt anything, either. So why not? > > > > More complicated, less tested code. For no practical benefit, it'll still > > be slower than posix shm if there's any memmory pressure. But if you > > want to apply it, go ahead, I won't cry louder than this email. > > > > I still think the mmap dsm implementation is a bad idea. We shouldn't > > put additional effort into it. If anything we should remove it. > > If we have it, we should improve it, or remove it. We might want to use > this code for something else in the future, so it should be improved > where feasible.
Meh. We don't put in effort into code that doesn't matter just because it might get used elsewhere some day. By that argument we'd need to performance optimize a lot of code. And actually, using that code somewhere else is more of a counter indication than a pro argument. MAP_NOSYNC isn't a general purpose flag. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
