00002_free_plpgsql_function_memory.patch

diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index a341cde2c14..8aad27a9028 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -2670,3 +2670,31 @@ plpgsql_HashTableDelete(PLpgSQL_function *function)
 	/* remove back link, which no longer points to allocated storage */
 	function->fn_hashkey = NULL;
 }
+
+/* Try to delete and release the plan cache from the hash table */
+void
+plpgsql_func_inval_callback(Datum arg, int cacheid, uint32 hashvalue)
+{
+	HASH_SEQ_STATUS scan;
+	plpgsql_HashEnt *entry;
+	uint32			funcOid_hashvalue;
+
+	Assert(cacheid == PROCOID);
+
+	hash_seq_init(&scan, plpgsql_HashTable);
+	while ((entry = (plpgsql_HashEnt *) hash_seq_search(&scan)))
+	{
+		funcOid_hashvalue = GetSysCacheHashValue1(PROCOID,
+												  ObjectIdGetDatum(entry->key.funcOid));
+		/* Ignore invalid entries */
+		if (entry->function == NULL)
+			continue;
+
+		/* hashvalue == 0 means a cache reset, must clear all state */
+		if (hashvalue == 0 || 
+			(cacheid == PROCOID && funcOid_hashvalue == hashvalue))
+		{
+			delete_function(entry->function);
+		}
+	}
+}
\ No newline at end of file
diff --git a/src/pl/plpgsql/src/pl_handler.c b/src/pl/plpgsql/src/pl_handler.c
index d8994538b76..5b2e50913ba 100644
--- a/src/pl/plpgsql/src/pl_handler.c
+++ b/src/pl/plpgsql/src/pl_handler.c
@@ -26,6 +26,7 @@
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
 #include "utils/varlena.h"
+#include "utils/inval.h"
 
 static bool plpgsql_extra_checks_check_hook(char **newvalue, void **extra, GucSource source);
 static void plpgsql_extra_warnings_assign_hook(const char *newvalue, void *extra);
@@ -202,6 +203,7 @@ _PG_init(void)
 	plpgsql_HashTableInit();
 	RegisterXactCallback(plpgsql_xact_cb, NULL);
 	RegisterSubXactCallback(plpgsql_subxact_cb, NULL);
+	CacheRegisterSyscacheCallback(PROCOID, plpgsql_func_inval_callback, (Datum) 0);
 
 	/* Set up a rendezvous point with optional instrumentation plugin */
 	plpgsql_plugin_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index cead9eb7263..20a006ca331 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -1263,6 +1263,7 @@ extern PLpgSQL_condition *plpgsql_parse_err_condition(char *condname);
 extern void plpgsql_adddatum(PLpgSQL_datum *newdatum);
 extern int	plpgsql_add_initdatums(int **varnos);
 extern void plpgsql_HashTableInit(void);
+extern void plpgsql_func_inval_callback(Datum arg, int cacheid, uint32 hashvalue);
 
 /*
  * Functions in pl_exec.c