Add RecoveryStopsHook for extensions to handle custom WAL records

Author: za-arthur

src/backend/access/transam/xlogrecovery.c

@@ -2620,6 +2620,9 @@ recoveryStopsBefore(XLogReaderState *record)
 	/* Otherwise we only consider stopping before COMMIT or ABORT records. */
 	if (XLogRecGetRmid(record) != RM_XACT_ID)
 		return false;
+	/* Check RecoveryStopsHook for custom records */
+	else if (RmgrIdIsCustom(XLogRecGetRmid(record)) && (RecoveryStopsHook != NULL))
+		return RecoveryStopsHook(record, true);
 
 	xact_info = XLogRecGetInfo(record) & XLOG_XACT_OPMASK;
 
@@ -2787,6 +2790,9 @@ recoveryStopsAfter(XLogReaderState *record)
 
 	if (rmid != RM_XACT_ID)
 		return false;
+	/* Check RecoveryStopsHook for custom records */
+	else if (RmgrIdIsCustom(XLogRecGetRmid(record)) && (RecoveryStopsHook != NULL))
+		return RecoveryStopsHook(record, false);
 
 	xact_info = info & XLOG_XACT_OPMASK;
 
@@ -4556,6 +4562,8 @@ GetXLogReplayRecPtr(TimeLineID *replayTLI)
 
 GetReplayXlogPtrHookType GetReplayXlogPtrHook = NULL;
 
+RecoveryStopsHookType RecoveryStopsHook = NULL;
+
 /*
  * Get effective latest redo apply position.
  *

src/include/access/xlogrecovery.h

@@ -50,6 +50,8 @@ typedef enum RecoveryPauseState
 
 typedef XLogRecPtr (*GetReplayXlogPtrHookType) (void);
 
+typedef bool (*RecoveryStopsHookType) (XLogReaderState *record, bool isBefore);
+
 /* User-settable GUC parameters */
 extern PGDLLIMPORT bool recoveryTargetInclusive;
 extern PGDLLIMPORT int recoveryTargetAction;
@@ -81,6 +83,12 @@ extern PGDLLIMPORT bool StandbyMode;
 /* Hook for extensions to tune replay xlog pointer */
 extern PGDLLIMPORT GetReplayXlogPtrHookType GetReplayXlogPtrHook;
 
+/*
+ * Hook for extensions to be able to decides to stop applying the WAL files
+ * based on custom WAL records.
+ */
+extern PGDLLIMPORT RecoveryStopsHookType RecoveryStopsHook;
+
 extern Size XLogRecoveryShmemSize(void);
 extern void XLogRecoveryShmemInit(void);