Add recovery_cleanup_hook

src/backend/utils/init/postinit.c

@@ -81,7 +81,7 @@ static void ClientCheckTimeoutHandler(void);
 static bool ThereIsAtLeastOneRole(void);
 static void process_startup_options(Port *port, bool am_superuser);
 static void process_settings(Oid databaseid, Oid roleid);
-
+recovery_cleanup_hook_type recovery_cleanup_hook = NULL;
 
 /*** InitPostgres support ***/
 
@@ -641,6 +641,9 @@ BaseInit(void)
 	 */
 	InitFileAccess();
 
+	if (recovery_cleanup_hook)
+		(*recovery_cleanup_hook) (void);
+
 	/*
 	 * Initialize statistics reporting. This needs to happen early to ensure
 	 * that pgstat's shutdown callback runs after the shutdown callbacks of

src/include/postmaster/postmaster.h

@@ -59,6 +59,10 @@ extern int	MaxLivePostmasterChildren(void);
 
 extern bool PostmasterMarkPIDForWorkerNotify(int);
 
+typedef void (*recovery_cleanup_hook_type)(void);
+
+extern PGDLLIMPORT recovery_cleanup_hook_type recovery_cleanup_hook;
+
 #ifdef EXEC_BACKEND
 extern pid_t postmaster_forkexec(int argc, char *argv[]);
 extern void SubPostmasterMain(int argc, char *argv[]) pg_attribute_noreturn();