Automatically terminate replication connections that are idle for more

than replication_timeout (a new GUC) milliseconds. The TCP timeout is often
too long, you want the master to notice a dead connection much sooner.
People complained about that in 9.0 too, but with synchronous replication
it's even more important to notice dead connections promptly.

Fujii Masao and Heikki Linnakangas

src/backend/utils/misc/guc.c

@@ -1855,6 +1855,16 @@ static struct config_int ConfigureNamesInt[] =
 		1000, 1, 10000, NULL, NULL
 	},
 
+	{
+		{"replication_timeout", PGC_SIGHUP, WAL_REPLICATION,
+			gettext_noop("Sets the maximum time to wait for WAL replication."),
+			NULL,
+			GUC_UNIT_MS
+		},
+		&replication_timeout,
+		60 * 1000, 0, INT_MAX, NULL, NULL
+	},
+
 	{
 		{"commit_delay", PGC_USERSET, WAL_SETTINGS,
 			gettext_noop("Sets the delay in microseconds between transaction commit and "