Fix for 68edd02: We need the hook anyway if we use long transactions

Author: za-arthur

pg_variables.c

@@ -80,6 +80,9 @@ static void makePackHTAB(Package *package, bool is_trans);
 static inline ChangedObject *makeChangedObject(TransObject *object,
 											   MemoryContext ctx);
 
+/* Hook functions */
+static void variable_ExecutorEnd(QueryDesc *queryDesc);
+
 #define CHECK_ARGS_FOR_NULL() \
 do { \
 	if (fcinfo->argnull[0]) \
@@ -110,6 +113,9 @@ static Oid LastTypeId = InvalidOid;
  */
 static HASH_SEQ_STATUS *LastHSeqStatus = NULL;
 
+/* Saved hook values for recall */
+static ExecutorEnd_hook_type prev_ExecutorEnd = NULL;
+
 /* This stack contains lists of changed variables and packages per each subxact level */
 static dlist_head *changesStack = NULL;
 static MemoryContext changesStackContext = NULL;
@@ -2125,6 +2131,23 @@ pgvTransCallback(XactEvent event, void *arg)
 		}
 }
 
+/*
+ * ExecutorEnd hook: clean up hash table sequential scan status
+ */
+static void
+variable_ExecutorEnd(QueryDesc *queryDesc)
+{
+	if (LastHSeqStatus)
+	{
+		hash_seq_term(LastHSeqStatus);
+		LastHSeqStatus = NULL;
+	}
+	if (prev_ExecutorEnd)
+		prev_ExecutorEnd(queryDesc);
+	else
+		standard_ExecutorEnd(queryDesc);
+}
+
 /*
  * Register callback function when module starts
  */
@@ -2133,6 +2156,10 @@ _PG_init(void)
 {
 	RegisterXactCallback(pgvTransCallback, NULL);
 	RegisterSubXactCallback(pgvSubTransCallback, NULL);
+
+	/* Install hooks. */
+	prev_ExecutorEnd = ExecutorEnd_hook;
+	ExecutorEnd_hook = variable_ExecutorEnd;
 }
 
 /*
@@ -2143,4 +2170,5 @@ _PG_fini(void)
 {
 	UnregisterXactCallback(pgvTransCallback, NULL);
 	UnregisterSubXactCallback(pgvSubTransCallback, NULL);
+	ExecutorEnd_hook = prev_ExecutorEnd;
 }