Reduce scope of changes for COPY FREEZE.

Allow support only for freezing tuples by explicit
command. Previous coding mistakenly extended
slightly beyond what was agreed as correct on -hackers.
So essentially a partial revoke of earlier work,
leaving just the COPY FREEZE command.

src/backend/access/heap/heapam.c

@@ -1875,13 +1875,11 @@ FreeBulkInsertState(BulkInsertState bistate)
  * The HEAP_INSERT_SKIP_FSM option is passed directly to
  * RelationGetBufferForTuple, which see for more info.
  *
- * HEAP_INSERT_COMMITTED should only be specified for inserts into
+ * HEAP_INSERT_FROZEN should only be specified for inserts into
  * relfilenodes created during the current subtransaction and when
  * there are no prior snapshots or pre-existing portals open.
- *
+ * This causes rows to be frozen, which is an MVCC violation and
- * HEAP_INSERT_FROZEN only has meaning when HEAP_INSERT_COMMITTED is
+ * requires explicit options chosen by user.
- * also set. This causes rows to be frozen, which is an MVCC violation
- * and requires explicit options chosen by user.
  *
  * Note that these options will be applied when inserting into the heap's
  * TOAST table, too, if the tuple requires any out-of-line data.
@@ -2086,10 +2084,9 @@ heap_prepare_insert(Relation relation, HeapTuple tup, TransactionId xid,
 	tup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
 	tup->t_data->t_infomask2 &= ~(HEAP2_XACT_MASK);
 	tup->t_data->t_infomask |= HEAP_XMAX_INVALID;
-	if (options & HEAP_INSERT_COMMITTED)
+	if (options & HEAP_INSERT_FROZEN)
 	{
 		tup->t_data->t_infomask |= HEAP_XMIN_COMMITTED;
-		if (options & HEAP_INSERT_FROZEN)
 		HeapTupleHeaderSetXmin(tup->t_data, FrozenTransactionId);
 	}
 	else

src/backend/commands/copy.c

@@ -1994,15 +1994,12 @@ CopyFrom(CopyState cstate)
 		 * which subtransaction created it is crucial for correctness
 		 * of this optimisation.
 		 */
-		if (ThereAreNoPriorRegisteredSnapshots() &&
+		if (cstate->freeze &&
+			ThereAreNoPriorRegisteredSnapshots() &&
 			ThereAreNoReadyPortals() &&
 			cstate->rel->rd_newRelfilenodeSubid == GetCurrentSubTransactionId())
-		{
-			hi_options |= HEAP_INSERT_COMMITTED;
-			if (cstate->freeze)
 			hi_options |= HEAP_INSERT_FROZEN;
 	}
-	}
 
 	if (cstate->freeze && (hi_options & HEAP_INSERT_FROZEN) == 0)
 		ereport(NOTICE,

src/include/access/heapam.h

@@ -26,8 +26,7 @@
 /* "options" flag bits for heap_insert */
 #define HEAP_INSERT_SKIP_WAL	0x0001
 #define HEAP_INSERT_SKIP_FSM	0x0002
-#define HEAP_INSERT_COMMITTED	0x0004
+#define HEAP_INSERT_FROZEN		0x0004
-#define HEAP_INSERT_FROZEN		0x0008
 
 typedef struct BulkInsertStateData *BulkInsertState;
 

src/test/regress/expected/copy2.out

@@ -260,8 +260,8 @@ TRUNCATE vistest;
 COPY vistest FROM stdin CSV;
 SELECT * FROM vistest;
  a  
----
+----
- a
+ a1
  b
 (2 rows)
 
@@ -270,19 +270,26 @@ TRUNCATE vistest;
 COPY vistest FROM stdin CSV;
 SELECT * FROM vistest;
  a  
----
+----
- d
+ d1
  e
 (2 rows)
 
 COMMIT;
+SELECT * FROM vistest;
+ a  
+----
+ d1
+ e
+(2 rows)
+
 BEGIN;
 TRUNCATE vistest;
 COPY vistest FROM stdin CSV FREEZE;
 SELECT * FROM vistest;
  a  
----
+----
- a
+ a2
  b
 (2 rows)
 
@@ -291,12 +298,19 @@ TRUNCATE vistest;
 COPY vistest FROM stdin CSV FREEZE;
 SELECT * FROM vistest;
  a  
----
+----
- d
+ d2
  e
 (2 rows)
 
 COMMIT;
+SELECT * FROM vistest;
+ a  
+----
+ d2
+ e
+(2 rows)
+
 BEGIN;
 TRUNCATE vistest;
 COPY vistest FROM stdin CSV FREEZE;
@@ -320,11 +334,11 @@ COPY vistest FROM stdin CSV FREEZE;
 NOTICE:  FREEZE option specified but pre-conditions not met
 SELECT * FROM vistest;
  a  
----
+----
  p
  g
  z
- d
+ d3
  e
 (5 rows)
 
@@ -332,10 +346,10 @@ COMMIT;
 CREATE FUNCTION truncate_in_subxact() RETURNS VOID AS
 $$
 BEGIN
-  SELECT * FROM nonexistent;
+	TRUNCATE vistest;
 EXCEPTION
   WHEN OTHERS THEN
-  	TRUNCATE vistest;
+	INSERT INTO vistest VALUES ('subxact failure');
 END;
 $$ language plpgsql;
 BEGIN;
@@ -349,16 +363,16 @@ SELECT truncate_in_subxact();
 COPY vistest FROM stdin CSV FREEZE;
 SELECT * FROM vistest;
  a  
----
+----
- d
+ d4
  e
 (2 rows)
 
 COMMIT;
 SELECT * FROM vistest;
  a  
----
+----
- d
+ d4
  e
 (2 rows)
 

src/test/regress/sql/copy2.sql

@@ -183,34 +183,37 @@ CREATE TABLE vistest (LIKE testeoc);
 BEGIN;
 TRUNCATE vistest;
 COPY vistest FROM stdin CSV;
-a
+a1
 b
 \.
 SELECT * FROM vistest;
 SAVEPOINT s1;
 TRUNCATE vistest;
 COPY vistest FROM stdin CSV;
-d
+d1
 e
 \.
 SELECT * FROM vistest;
 COMMIT;
+SELECT * FROM vistest;
 
 BEGIN;
 TRUNCATE vistest;
 COPY vistest FROM stdin CSV FREEZE;
-a
+a2
 b
 \.
 SELECT * FROM vistest;
 SAVEPOINT s1;
 TRUNCATE vistest;
 COPY vistest FROM stdin CSV FREEZE;
-d
+d2
 e
 \.
 SELECT * FROM vistest;
 COMMIT;
+SELECT * FROM vistest;
+
 BEGIN;
 TRUNCATE vistest;
 COPY vistest FROM stdin CSV FREEZE;
@@ -230,7 +233,7 @@ SAVEPOINT s1;
 TRUNCATE vistest;
 ROLLBACK TO SAVEPOINT s1;
 COPY vistest FROM stdin CSV FREEZE;
-d
+d3
 e
 \.
 SELECT * FROM vistest;
@@ -238,17 +241,17 @@ COMMIT;
 CREATE FUNCTION truncate_in_subxact() RETURNS VOID AS
 $$
 BEGIN
-  SELECT * FROM nonexistent;
+	TRUNCATE vistest;
 EXCEPTION
   WHEN OTHERS THEN
-  	TRUNCATE vistest;
+	INSERT INTO vistest VALUES ('subxact failure');
 END;
 $$ language plpgsql;
 BEGIN;
 INSERT INTO vistest VALUES ('z');
 SELECT truncate_in_subxact();
 COPY vistest FROM stdin CSV FREEZE;
-d
+d4
 e
 \.
 SELECT * FROM vistest;