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

Thanks!

At Mon, 6 Feb 2023 13:10:01 +0000, "Takamichi Osumi (Fujitsu)" <osumi.takamichi@fujitsu.com> wrote in 
> The attached patch v29 has included your changes.

catalogs.sgml

+      <para>
+       The minimum delay (ms) for applying changes.
+      </para></entry>

I think we don't use unit symbols that way. Namely I think we would
write it as "The minimum delay for applying changes in milliseconds"


alter_subscription.sgml

       are <literal>slot_name</literal>,
       <literal>synchronous_commit</literal>,
       <literal>binary</literal>, <literal>streaming</literal>,
-      <literal>disable_on_error</literal>, and
-      <literal>origin</literal>.
+      <literal>disable_on_error</literal>,
+      <literal>origin</literal>, and
+      <literal>min_apply_delay</literal>.
      </para>

By the way, is there any rule for the order among the words? They
don't seem in alphabetical order nor in the same order to the
create_sbuscription page.  (I seems like in the order of SUBOPT_*
symbols, but I'm not sure it's a good idea..)


subscriptioncmds.c

+                    if (opts.streaming == LOGICALREP_STREAM_PARALLEL &&
+                        !IsSet(opts.specified_opts, SUBOPT_MIN_APPLY_DELAY) && sub->minapplydelay > 0)
..
+                    if (opts.min_apply_delay > 0 &&
+                        !IsSet(opts.specified_opts, SUBOPT_STREAMING) && sub->stream == LOGICALREP_STREAM_PARALLEL)

Don't we wrap the lines?


worker.c

+        if (wal_receiver_status_interval > 0 &&
+            diffms > wal_receiver_status_interval * 1000L)
+        {
+            WaitLatch(MyLatch,
+                      WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
+                      wal_receiver_status_interval * 1000L,
+                      WAIT_EVENT_RECOVERY_APPLY_DELAY);
+            send_feedback(last_received, true, false, true);
+        }
+        else
+            WaitLatch(MyLatch,
+                      WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
+                      diffms,
+                      WAIT_EVENT_RECOVERY_APPLY_DELAY);

send_feedback always handles the case where
wal_receiver_status_interval == 0. thus we can simply wait for
min(wal_receiver_status_interval, diffms) then call send_feedback()
unconditionally.


-start_apply(XLogRecPtr origin_startpos)
+start_apply(void)

-LogicalRepApplyLoop(XLogRecPtr last_received)
+LogicalRepApplyLoop(void)

Does this patch requires this change?

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center