On Thu, Jan 15, 2026 at 09:47:39AM +0800, lchch1990@sina.cn wrote:
> I am thinking about why pg_rewind need wal_log_hints or data_checksums which significantly
> limits its usability. I research somewhere can can only find it's for against data
> corruption in code comment.
Hint bints can be set on a page, and we *have to* WAL log these pages
so as pg_rewind can track the modified blocks, or we would corrupt a
data folder after a rewind. See around this thread about the original
description of the issue:
https://www.postgresql.org/message-id/519E5493.5060800@vmware.com
> Here i want to introduce a way to solve the case above:
> We need record all transaction ID commited after diverge record and research more wal
> before diverge record, we need to find a start lsn(lsn_s) which older than all the
> transactions. And we should read from lsn_s to diverge lsn to collect influenced pages
> by the transactions. So we can copy them at the rewind phase.
How is a method based on the tracking of transaction IDs and the
modified blocks not going to be more costly than the current method
where we are able to track the modified blocks directly in the WAL
records?
--
Michael
