Curt Sampson <cjs@cynic.net> writes:
> This should also allow us to disable completely the ping-pong writes
> if we have a disk subsystem that we trust.
If we have a disk subsystem we trust, we just disable fsync on the
WAL and the performance issue largely goes away.
I concur with Bruce: the reason we keep page images in WAL is to
minimize the number of places we have to fsync, and thus the amount of
head movement required for a commit. Putting the page images elsewhere
cannot be a win AFAICS.
> Well, whether or not there's a cheap way depends on whether you consider
> fsync to be cheap. :-)
It's never cheap :-(
regards, tom lane
