RE: Failed transaction statistics to measure the logical replication progress

On Wednesday, December 22, 2021 6:14 PM osumi.takamichi@fujitsu.com <osumi.takamichi@fujitsu.com> wrote:
> 
> Attached the new patch v19.
> 

Thanks for your patch. I think it's better if you could add this patch to the commitfest.
Here are some comments:

1)
+       <structfield>commit_count</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of transactions successfully applied in this subscription.
+       Both COMMIT and COMMIT PREPARED increment this counter.
+      </para></entry>
+     </row>
...

I think the commands (like COMMIT, COMMIT PREPARED ...) can be surrounded with
"<command> </command>", thoughts?

2)
+extern void pgstat_report_subworker_xact_end(LogicalRepWorker *repWorker,
+                                             LogicalRepMsgType command,
+                                             bool bforce);

Should "bforce" be "force"?

3)
+ *  This should be called before the call of process_syning_tables() so to not

"process_syning_tables()" should be "process_syncing_tables()".

4)
+void
+pgstat_send_subworker_xact_stats(LogicalRepWorker *repWorker, bool force)
+{
+    static TimestampTz last_report = 0;
+    PgStat_MsgSubWorkerXactEnd msg;
+
+    if (!force)
+    {
...
+        if (!TimestampDifferenceExceeds(last_report, now, PGSTAT_STAT_INTERVAL))
+            return;
+        last_report = now;
+    }
+
...
+    if (repWorker->commit_count == 0 && repWorker->abort_count == 0)
+        return;
...

I think it's better to check commit_count and abort_count first, then check if
reach PGSTAT_STAT_INTERVAL.
Otherwise if commit_count and abort_count are 0, it is possible that the value
of last_report has been updated but it didn't send stats in fact. In this case,
last_report is not the real time that send last message.

Regards,
Tang