Fix walsender handling of postmaster shutdown, to not go into endless loop.

hlinnaka · hlinnaka · commit 9c0e2b918252 · 2012-10-08T13:32:14.000+03:00
This bug was introduced by my patch to use the regular die/quickdie signal
handlers in walsender processes. I tried to make walsender exit at next
CHECK_FOR_INTERRUPTS() by setting ProcDiePending, but that's not enough, you
need to set InterruptPending too. On second thoght, it was not a very good
way to make walsender exit anyway, so use proc_exit(0) instead.

Also, send a CommandComplete message before exiting; that's what we did
before, and you get a nicer error message in the standby that way.

Reported by Thom Brown.
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
@@ -711,8 +711,11 @@ WalSndLoop(void)
 				XLogSend(output_message, &caughtup);
 				if (caughtup && !pq_is_send_pending())
 				{
-					ProcDiePending = true;
-					continue;	/* don't want to wait more */
+					/* Inform the standby that XLOG streaming is done */
+					pq_puttextmessage('C', "COPY 0");
+					pq_flush();
+
+					proc_exit(0);
 				}
 			}
 		}

Original file line number	Diff line number	Diff line change
`@@ -711,8 +711,11 @@ WalSndLoop(void)`
`711`	`711`	`XLogSend(output_message, &caughtup);`
`712`	`712`	`if (caughtup && !pq_is_send_pending())`
`713`	`713`	`{`
`714`		`- ProcDiePending = true;`
`715`		`- continue; /* don't want to wait more */`
	`714`	`+ /* Inform the standby that XLOG streaming is done */`
	`715`	`+ pq_puttextmessage('C', "COPY 0");`
	`716`	`+ pq_flush();`
	`717`	`+`
	`718`	`+ proc_exit(0);`
`716`	`719`	`}`
`717`	`720`	`}`
`718`	`721`	`}`