Bruce Momjian wrote:
> Yes. If you were doing multiple WAL writes before transaction fsync,
> you would be fsyncing every write, rather than doing two writes and
> fsync'ing them both. I wonder if larger transactions would find
> open_sync slower?
No hard numbers, but I remember testing fsync vs open_sync something ago
on 7.3.x.
open_sync was blazingly fast for pgbench, but for when we switched our
development database over to open_sync, things slowed to a crawl.
This was some months ago, and I might be wrong, so take it with a grain
of salt. It was on Red Hat 8's Linux kernel 2.4.18, I think. YMMV.
Will be testing it real soon tonight, if possible.