Re: Time delayed LR (WAS Re: logical replication restrictions)

On Mon, Feb 27, 2023 at 2:21 PM Hayato Kuroda (Fujitsu)
<kuroda.hayato@fujitsu.com> wrote:
>

Few comments:
1.
+ /*
+ * If we've requested to shut down, exit the process.
+ *
+ * Note that WalSndDone() cannot be used here because the delaying
+ * changes will be sent in the function.
+ */
+ if (got_STOPPING)
+ {
+ QueryCompletion qc;
+
+ /* Inform the standby that XLOG streaming is done */
+ SetQueryCompletion(&qc, CMDTAG_COPY, 0);
+ EndCommand(&qc, DestRemote, false);
+ pq_flush();

Do we really need to do anything except for breaking the loop and let
the exit handling happen in the main loop when 'got_STOPPING' is set?
AFAICS, this is what we are doing in some other palces (See
WalSndWaitForWal). Won't that work? It seems that will help us sending
all the pending WAL.

2.
+ /* Try to flush pending output to the client */
+ if (pq_flush_if_writable() != 0)
+ WalSndShutdown();

Is there a reason to try flushing here?

Apart from the above, I have made a few changes in the comments in the
attached diff patch. If you agree with those then please include them
in the next version.

--
With Regards,
Amit Kapila.