Re: pgsql: Prevent tuples to be marked as dead in subtransactions on standb

On Tue, Dec 12, 2023 at 11:06 AM Michael Paquier <michael@paquier.xyz> wrote:
> Prevent tuples to be marked as dead in subtransactions on standbys

I don't think this is a good commit message. It's totally unclear what
it means, and when I opened up the diff to try to see what was
changed, it looked nothing like what I expected.

I think a better message would have been something like
"startedInRecovery flag must be propagated to subtransactions". And I
think there should have been some analysis in the commit message or
the comments within the commit itself of whether it was intended that
this be propagated to subtransactions or not. It's hard to understand
why the flag would have been placed in the TransactionState if it
applied globally to the transaction and all subtransactions, but maybe
that's what happened.

Instead of discussing that issue, your commit message focuses in the
user-visible consequences, but in a sort of baffling way. The
statement that "Dead tuples are ignored and are not marked as dead
during recovery," for example, is clearly false on its face. If
recovery didn't mark dead tuples as dead, it would be completely
broken.

--
Robert Haas
EDB: http://www.enterprisedb.com