Fix for 68edd02: Do not call hash_seq_term(), we can't trust to its pointer in the callback function

Author: za-arthur

expected/pg_variables.out

@@ -553,20 +553,6 @@ SELECT pgv_insert('vars3', 'r1', row(1, 1));
 ERROR:  new record structure differs from variable "r1" structure
 SELECT pgv_insert('vars3', 'r1', row('str1', 'str1'));
 ERROR:  new record structure differs from variable "r1" structure
-SELECT pgv_select('vars3', 'r1') LIMIT 2;
- pgv_select 
-------------
- (,strNULL)
- (1,str11)
-(2 rows)
-
-SELECT pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
- pgv_select 
-------------
- (2,)
- (0,str00)
-(2 rows)
-
 SELECT pgv_select('vars3', 'r1');
  pgv_select 
 ------------
@@ -657,6 +643,35 @@ SELECT pgv_exists('vars3', 'r1');
 
 SELECT pgv_select('vars2', 'j1');
 ERROR:  variable "j1" requires "jsonb" value
+-- Tests for SRF's sequential scan of an internal hash table
+DO
+$$BEGIN
+    PERFORM pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
+    PERFORM pgv_select('vars3', 'r3');
+END$$;
+ERROR:  unrecognized variable "r3"
+CONTEXT:  SQL statement "SELECT pgv_select('vars3', 'r3')"
+PL/pgSQL function inline_code_block line 3 at PERFORM
+-- Check that the hash table was cleaned up after rollback
+SELECT pgv_select('vars3', 'r1', 1);
+ pgv_select 
+------------
+ 
+(1 row)
+
+SELECT pgv_select('vars3', 'r1') LIMIT 2;
+ pgv_select 
+------------
+ (,strNULL)
+ (2,)
+(2 rows)
+
+SELECT pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
+ pgv_select 
+------------
+ (0,str00)
+(1 row)
+
 -- Manipulate variables
 SELECT * FROM pgv_list() order by package, name;
  package |   name   | is_transactional 

pg_variables.c

@@ -2121,14 +2121,9 @@ pgvTransCallback(XactEvent event, void *arg)
 		}
 	}
 
-	if (event == XACT_EVENT_PARALLEL_COMMIT || event == XACT_EVENT_COMMIT ||
-		event == XACT_EVENT_PREPARE ||
-		event == XACT_EVENT_PARALLEL_ABORT || event == XACT_EVENT_ABORT)
+	if (event == XACT_EVENT_PARALLEL_ABORT || event == XACT_EVENT_ABORT)
 		if (LastHSeqStatus)
-		{
-			hash_seq_term(LastHSeqStatus);
 			LastHSeqStatus = NULL;
-		}
 }
 
 /*

sql/pg_variables.sql

@@ -153,9 +153,6 @@ SELECT pgv_insert('vars3', 'r1', row(1, 'str1', 'str2'));
 SELECT pgv_insert('vars3', 'r1', row(1, 1));
 SELECT pgv_insert('vars3', 'r1', row('str1', 'str1'));
 
-SELECT pgv_select('vars3', 'r1') LIMIT 2;
-SELECT pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
-
 SELECT pgv_select('vars3', 'r1');
 SELECT pgv_select('vars3', 'r1', 1);
 SELECT pgv_select('vars3', 'r1', 0);
@@ -175,6 +172,17 @@ SELECT pgv_exists('vars3', 'r3');
 SELECT pgv_exists('vars3', 'r1');
 SELECT pgv_select('vars2', 'j1');
 
+-- Tests for SRF's sequential scan of an internal hash table
+DO
+$$BEGIN
+    PERFORM pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
+    PERFORM pgv_select('vars3', 'r3');
+END$$;
+-- Check that the hash table was cleaned up after rollback
+SELECT pgv_select('vars3', 'r1', 1);
+SELECT pgv_select('vars3', 'r1') LIMIT 2;
+SELECT pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
+
 -- Manipulate variables
 SELECT * FROM pgv_list() order by package, name;
 SELECT package FROM pgv_stats() order by package;