Add online_ugrade_path option

Author: knizhnik

src/backend/postmaster/postmaster.c

@@ -354,6 +354,8 @@ bool		ClientAuthInProgress = false;	/* T during new-client
 
 bool		redirection_done = false;	/* stderr redirected for syslogger? */
 
+char* OnlineUpgradePath = (char*)"";
+
 /* received START_AUTOVAC_LAUNCHER signal */
 static volatile sig_atomic_t start_autovac_launcher = false;
 
@@ -565,10 +567,13 @@ static void
 UpgradePostgres(void)
 {
 #ifdef EXEC_BACKEND
-	char* PostmasterArgs[] = {"/home/knizhnik/postgresql/dist/bin/postgres", "-U", "-D", "." ,NULL};
+	char* PostmasterArgs[] = {"postgres", "-U", "-D", "." ,NULL};
 	BackendParameters param;
 	FILE	   *fp;
 
+	if (*OnlineUpgradePath == '\0')
+		elog(ERROR, "Online upgrade path was not specified: alter system set online_ugrade_path='...' ; select pg_reload_conf()");
+
 	IsOnlineUpgrade = true;
 	TerminateChildren(SIGTERM);
 	if (CheckpointerPID != 0)
@@ -605,10 +610,11 @@ UpgradePostgres(void)
 		return;
 	}
 
-	elog(LOG, "Upgrade postgres");
+	elog(LOG, "Upgrade postgres to %s", OnlineUpgradePath);
+	PostmasterArgs[0] = psprintf("%s/postgres", OnlineUpgradePath);
 	execv(PostmasterArgs[0], PostmasterArgs);
 #else
-	elog(LOG, "Online upgrade is possible only postgres configured with EXEC_BACKEND");
+	elog(LOG, "Online upgrade is possible only for postgres configured with EXEC_BACKEND");
 #endif
 }
 

src/backend/utils/misc/guc.c

@@ -3668,6 +3668,17 @@ static struct config_string ConfigureNamesString[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"online_upgrade_path", PGC_SIGHUP, FILE_LOCATIONS,
+		 gettext_noop("Specify path to binaries of new Postgres version for online upgrade"),
+		 NULL,
+		 GUC_SUPERUSER_ONLY
+		},
+		&OnlineUpgradePath,
+		"",
+		NULL, NULL, NULL
+	},
+
 	{
 		{"krb_server_keyfile", PGC_SIGHUP, CONN_AUTH_AUTH,
 			gettext_noop("Sets the location of the Kerberos server key file."),

src/include/postmaster/postmaster.h

@@ -29,6 +29,7 @@ extern bool log_hostname;
 extern bool enable_bonjour;
 extern char *bonjour_name;
 extern bool restart_after_crash;
+extern char* OnlineUpgradePath;
 
 #ifdef WIN32
 extern HANDLE PostmasterHandle;