Fix bug so logical rep launcher saves correctly time of last startup of worker.

MasaoFujii · MasaoFujii · commit 9f11fcec6624 · 2017-04-28T06:35:00.000+09:00
Previously the logical replication launcher stored the last timestamp when it started the worker, in the local variable "last_start_time", in order to check whether wal_retrive_retry_interval elapsed since the last startup of worker. If it has elapsed, the launcher sees pg_subscription and starts new worker if necessary. This is for limitting the startup of worker to once a wal_retrieve_retry_interval. The bug was that the variable "last_start_time" was defined and always initialized with 0 at the beginning of the launcher's main loop. So even if it's set to the last timestamp in later phase of the loop, it's always reset to 0. Therefore the launcher could not check correctly whether wal_retrieve_retry_interval elapsed since the last startup. This patch moves the variable "last_start_time" outside the main loop so that it will not be reset. Reviewed-by: Petr Jelinek Discussion: http://postgr.es/m/CAHGQGwGJrPO++XM4mFENAwpy1eGXKsGdguYv43GUgLgU-x8nTQ@mail.gmail.com
diff --git a/src/backend/replication/logical/launcher.c b/src/backend/replication/logical/launcher.c
@@ -781,6 +781,8 @@ ApplyLauncherWakeup(void)
 void
 ApplyLauncherMain(Datum main_arg)
 {
+	TimestampTz		last_start_time = 0;
+
 	ereport(DEBUG1,
 			(errmsg("logical replication launcher started")));
 
@@ -812,7 +814,6 @@ ApplyLauncherMain(Datum main_arg)
 		MemoryContext	subctx;
 		MemoryContext	oldctx;
 		TimestampTz		now;
-		TimestampTz		last_start_time = 0;
 		long			wait_time = DEFAULT_NAPTIME_PER_CYCLE;
 
 		now = GetCurrentTimestamp();
