Re: [pgsql-hackers-win32] win32 performance - fsync question

Greg Stark <gsstark(at)mit(dot)edu> writes:
> I'm a bit surprised that the write-cache lead to a corrupt database, and not
> merely lost transactions. I had the impression that drives still handled the
> writes in the order received.

There'd be little point in having a cache if they did, I should think.
I thought the point of the cache was to allow the disk to schedule I/O
in an order that minimizes seek time (ie, such a disk has got its own
elevator queue or similar).

> You may find that if you check this case again that the "usually no data
> corruption" is actually "usually lost transactions but no corruption".

That's a good point, but it seems difficult to be sure of the last
reportedly-committed transaction in a powerfail situation. Maybe if
you drive the test from a client on another machine?

regards, tom lane