From: Michael Paquier <michael@paquier.xyz>
> CRC calculation would unlikely be the bottleneck here, no? I would assume
> that the extra lseek() calls needed to look after the record data to be more
> harmful.
Maybe, although I'm not sure lseek() is necessary. I simply thought walsender was designed to just read and send WAL
withoutcaring about other things for maximal speed.
> Yep. However, I would worry much more about the case of cold archives. In
> my experience, there are higher risks to get a WAL segment corrupted because
> it was on disk and that this disk got corrupted. Transmission is a one-time
> short operation. Cold archives could stay on disk for weeks before getting
> reused in WAL replay.
Yes, I think cold archives should be checked regularly. pg_verifybackup and pg_waldump can be used for it, can't they?
Regards
Takayuki Tsunakawa