On Wed, Aug 7, 2024 at 4:18 PM Greg Sabino Mullane <htamfids@gmail.com> wrote:
>
> On Wed, Aug 7, 2024 at 4:43 AM Michael Banck <mbanck@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
defaultchanges. I mean, I feel wal_log_hints should probably default to on as well, but I've honestly never really
givenit much thought because my fingers are trained to type "initdb -k". I've been using data checksums for roughly a
decadenow. I think the only time I've NOT used checksums was when I was doing checksum overhead measurements, or
hackingon 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.
