On Wed, Aug 7, 2024 at 4:18 PM Greg Sabino Mullane <htamf...@gmail.com> wrote: > > On Wed, Aug 7, 2024 at 4:43 AM Michael Banck <mba...@gmx.net> wrote: >> >> I think the last time we dicussed this the consensus was that >> computational overhead of computing the checksums is pretty small for >> most systems (so the above change seems warranted regardless of whether >> we switch the default), but turning on wal_compression also turns on >> wal_log_hints, which can increase WAL by quite a lot. Maybe this is [..] > > > Yeah, that seems something beyond this patch? Certainly we should mention > wal_compression in the release notes if the default changes. I mean, I feel > wal_log_hints should probably default to on as well, but I've honestly never > really given it much thought because my fingers are trained to type "initdb > -k". I've been using data checksums for roughly a decade now. I think the > only time I've NOT used checksums was when I was doing checksum overhead > measurements, or hacking on the pg_checksums program.
Maybe I don't understand something, but just to be clear: wal_compression (mentioned above) is not turning wal_log_hints on, just the wal_log_hints needs to be on when using data checksums (implicitly, by the XLogHintBitIsNeeded() macro). I suppose Michael was thinking about the wal_log_hints earlier (?) -J.
