Re: Disable WAL logging to speed up data loading

On Wed, 2020-10-28 at 04:11 +0000, osumi.takamichi@fujitsu.com wrote:
> I wrote and attached the first patch to disable WAL logging.
> This patch passes the regression test of check-world already
> and is formatted by pgindent.

Without reading the code, I have my doubts about that feature.

While it clearly will improve performance, it opens the door to
data loss.  People will use it to speed up their data loads and
then be unhappy if they cannot use their backups to recover from
a problem.

What happens if you try to do archive recovery across a time where
wal_level was "none"?  Will the recovery process fail, as it should,
or will you end up with data corruption?

We already have a performance-related footgun in the shape of
fsync = off.  Do we want to add another one?

Yours,
Laurenz Albe