Re: Moving pgstat.stat and pgstat.tmp

Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> But then I thought, why do we need it to be a file
> at all?  Why not use a mmap'ed memory area or something like that, and
> only write it to a file on postmaster shutdown?

Yeah, we definitely need some other technology for this.  The difficulty
is in dealing with a highly variably sized chunk of data --- our
existing shmem approach won't work well, and once you get away from that
the old portability question raises its head.

There's also a synchronization issue: how can the stats collector make
updates appear atomic?  mmap by itself doesn't solve that AFAIK.

            regards, tom lane