Dear Horiguchi-san, > > Thus how about before entering an apply_delay, logrep worker sending a > > kind of crafted feedback, which reports commit_data.end_lsn as > > flushpos? A little tweak is needed in send_feedback() but seems to > > work.. > > Thanks for replying! I tested your saying but it could not work well... > > I made PoC based on the latest time-delayed patches [1] for non-streaming > case. > Apply workers that are delaying applications send begin_data.final_lsn as > recvpos > and flushpos in send_feedback().
Maybe I misunderstood what you said... I have also found that sentPtr is not the actual sent position, but the starting point of the next WAL. You can see the comment below. ``` /* * How far have we sent WAL already? This is also advertised in * MyWalSnd->sentPtr. (Actually, this is the next WAL location to send.) */ static XLogRecPtr sentPtr = InvalidXLogRecPtr; ``` We must use end_lsn for crafting messages to cheat the walsender, but such records are included in COMMIT, not in BEGIN for the non-streaming case. But if workers are delayed in apply_handle_commit(), will they hold locks for database objects for a long time and it causes another issue. Best Regards, Hayato Kuroda FUJITSU LIMITED
