Re: Disable page writes when fsync off, add GUC

* Bruce Momjian (pgman(at)candle(dot)pha(dot)pa(dot)us) wrote:
> This patch disables page writes to WAL when fsync is off, because with
> no fsync guarantee, the page write recovery isn't useful.

This doesn't seem quite right to me. What happens with PITR? And
Postgres crashes? While many people seriously distrust running w/ fsync
off, I'm sure there's quite a few folks which do.

> This also adds a full_page_writes GUC to turn off page writes to WAL.
> Some people might not want full_page_writes, but still might want fsync.

Adding an option to not do page writes to WAL seems fine to me, but I
think WAL writes should be on by default, even in the fsync=off case.
If people want to turn it off, fine, for either case since we expect
they understand what it means to have it turned off, but I don't think
the two options should be coupled as is being proposed.

Thanks,

Stephen