On Wed, Oct 25, 2023 at 4:23 PM José Neves <rafanev...@msn.com> wrote: > > Ok, I see. In that situation is safe indeed, as the offset is lower than the > current transaction commit. > But I think that I asked the wrong question. I guess that the right question > is: Can we receive a keep-alive message with an LSN offset bigger than the > commit of the open or following transactions? > Something like: > > BEGIN LSN001 > INSERT LSN002 > KEEP LIVE LSN006 > UPDATE LSN004 > COMMIT LSN005 > > Or: > > KEEP LIVE LSN006 > BEGIN LSN001 > INSERT LSN002 > UPDATE LSN004 > COMMIT LSN005 > KEEP LIVE LSN007 >
AFAIU the code in walsender this isn't possible. Keep alive sends the LSN of the last WAL record it read (sentPtr). Upon reading a commit WAL record, the whole transaction is decoded. Till that point sentPtr is not updated. Please take a look at XLogSendLogical(void) and the places where WalSndKeepaliveIfNecessary() is called. -- Best Wishes, Ashutosh Bapat
