Report statistics in logical replication workers

Author: Stas Kelvich <s.kelvich@postgrespro.ru>
Author: Petr Jelinek <petr.jelinek@2ndquadrant.com>
Reported-by: Fujii Masao <masao.fujii@gmail.com>

src/backend/postmaster/pgstat.c

@@ -769,9 +769,10 @@ allow_immediate_pgstat_restart(void)
 /* ----------
  * pgstat_report_stat() -
  *
- *	Called from tcop/postgres.c to send the so far collected per-table
- *	and function usage statistics to the collector.  Note that this is
- *	called only when not within a transaction, so it is fair to use
+ *	Must be called by processes that performs DML: tcop/postgres.c, logical
+ *	receiver processes, SPI worker, etc. to send the so far collected
+ *	per-table and function usage statistics to the collector.  Note that this
+ *	is called only when not within a transaction, so it is fair to use
  *	transaction stop time as an approximation of current time.
  * ----------
  */

src/backend/replication/logical/tablesync.c

@@ -114,9 +114,15 @@ StringInfo	copybuf = NULL;
 static void pg_attribute_noreturn()
 finish_sync_worker(void)
 {
-	/* Commit any outstanding transaction. */
+	/*
+	 * Commit any outstanding transaction. This is the usual case, unless
+	 * there was nothing to do for the table.
+	 */
 	if (IsTransactionState())
+	{
 		CommitTransactionCommand();
+		pgstat_report_stat(false);
+	}
 
 	/* And flush all writes. */
 	XLogFlush(GetXLogWriteRecPtr());

src/backend/replication/logical/worker.c

@@ -462,6 +462,7 @@ apply_handle_commit(StringInfo s)
 	/* Process any tables that are being synchronized in parallel. */
 	process_syncing_tables(commit_data.end_lsn);
 
+	pgstat_report_stat(false);
 	pgstat_report_activity(STATE_IDLE, NULL);
 }