diff --git a/src/backend/utils/cache/inval.c b/src/backend/utils/cache/inval.c
index f5775880416..4fbca7b5711 100644
--- a/src/backend/utils/cache/inval.c
+++ b/src/backend/utils/cache/inval.c
@@ -240,6 +240,9 @@ static TransInvalidationInfo *transInvalInfo = NULL;
 /* GUC storage */
 int			debug_discard_caches = 0;
 
+/* Hook for extensions to receive custom invalidation messages */
+ReceiveCustomInvalMessage_hook_type ReceiveCustomInvalMessage_hook = NULL;
+
 /*
  * Dynamically-registered callback functions.  Current implementation
  * assumes there won't be enough of these to justify a dynamically resizable
@@ -827,6 +830,18 @@ InvalidateSystemCaches(void)
 	InvalidateSystemCachesExtended(false);
 }
 
+/*
+ * ReceiveCustomInvalMessage
+ *		Call the ReceiveCustomInvalMessage_hook if set, allowing extensions
+ *		to process their own invalidation messages.
+ */
+void
+ReceiveCustomInvalMessage(void)
+{
+	if (ReceiveCustomInvalMessage_hook)
+		(*ReceiveCustomInvalMessage_hook) ();
+}
+
 /*
  * AcceptInvalidationMessages
  *		Read and process invalidation messages from the shared invalidation
@@ -838,6 +853,9 @@ InvalidateSystemCaches(void)
 void
 AcceptInvalidationMessages(void)
 {
+	/* Process any messages from external sources first. */
+	ReceiveCustomInvalMessage();
+
 	ReceiveSharedInvalidMessages(LocalExecuteInvalidationMessage,
 								 InvalidateSystemCaches);
 
diff --git a/src/include/utils/inval.h b/src/include/utils/inval.h
index 69498b9f77f..1ab129f9376 100644
--- a/src/include/utils/inval.h
+++ b/src/include/utils/inval.h
@@ -20,12 +20,17 @@
 
 extern PGDLLIMPORT int debug_discard_caches;
 
+/* Hook for extensions to receive custom invalidation messages */
+typedef void (*ReceiveCustomInvalMessage_hook_type) (void);
+extern PGDLLIMPORT ReceiveCustomInvalMessage_hook_type ReceiveCustomInvalMessage_hook;
+
 typedef void (*SyscacheCallbackFunction) (Datum arg, int cacheid, uint32 hashvalue);
 typedef void (*RelcacheCallbackFunction) (Datum arg, Oid relid);
 typedef void (*UsercacheCallbackFunction) (Datum arg, Oid arg1, Oid arg2, Oid arg3);
 
 
 extern void AcceptInvalidationMessages(void);
+extern void ReceiveCustomInvalMessage(void);
 
 extern void AtEOXact_Inval(bool isCommit);