From 60f227316c0ebf5f4f8296f11cedc9360e9cb8ae Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Tue, 28 Nov 2023 11:59:09 +0200
Subject: [PATCH] Fix assertions with RI triggers in heap_update and
heap_delete.
If the tuple being updated is not visible to the crosscheck snapshot,
we return TM_Updated but the assertions would not hold in that case.
Move them to before the cross-check.
Fixes bug #17893. Backpatch to all supported versions.
Author: Alexander Lakhin
Backpatch-through: 12
Discussion: https://www.postgresql.org/message-id/17893-35847009eec517b5%40postgresql.org
---
src/backend/access/heap/heapam.c | 41 ++++++++++++---------
src/include/access/tableam.h | 4 +-
src/test/isolation/expected/fk-snapshot.out | 22 +++++++++++
src/test/isolation/specs/fk-snapshot.spec | 17 ++++++++-
4 files changed, 64 insertions(+), 20 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 14de8158d49..f9387153595 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2708,13 +2708,7 @@ l1:
result = TM_Deleted;
}
- if (crosscheck != InvalidSnapshot && result == TM_Ok)
- {
- /* Perform additional check for transaction-snapshot mode RI updates */
- if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
- result = TM_Updated;
- }
-
+ /* sanity check the result HeapTupleSatisfiesUpdate() and the logic above */
if (result != TM_Ok)
{
Assert(result == TM_SelfModified ||
@@ -2724,6 +2718,17 @@ l1:
Assert(!(tp.t_data->t_infomask & HEAP_XMAX_INVALID));
Assert(result != TM_Updated ||
!ItemPointerEquals(&tp.t_self, &tp.t_data->t_ctid));
+ }
+
+ if (crosscheck != InvalidSnapshot && result == TM_Ok)
+ {
+ /* Perform additional check for transaction-snapshot mode RI updates */
+ if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
+ result = TM_Updated;
+ }
+
+ if (result != TM_Ok)
+ {
tmfd->ctid = tp.t_data->t_ctid;
tmfd->xmax = HeapTupleHeaderGetUpdateXid(tp.t_data);
if (result == TM_SelfModified)
@@ -3342,16 +3347,7 @@ l2:
result = TM_Deleted;
}
- if (crosscheck != InvalidSnapshot && result == TM_Ok)
- {
- /* Perform additional check for transaction-snapshot mode RI updates */
- if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
- {
- result = TM_Updated;
- Assert(!ItemPointerEquals(&oldtup.t_self, &oldtup.t_data->t_ctid));
- }
- }
-
+ /* Sanity check the result HeapTupleSatisfiesUpdate() and the logic above */
if (result != TM_Ok)
{
Assert(result == TM_SelfModified ||
@@ -3361,6 +3357,17 @@ l2:
Assert(!(oldtup.t_data->t_infomask & HEAP_XMAX_INVALID));
Assert(result != TM_Updated ||
!ItemPointerEquals(&oldtup.t_self, &oldtup.t_data->t_ctid));
+ }
+
+ if (crosscheck != InvalidSnapshot && result == TM_Ok)
+ {
+ /* Perform additional check for transaction-snapshot mode RI updates */
+ if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
+ result = TM_Updated;
+ }
+
+ if (result != TM_Ok)
+ {
tmfd->ctid = oldtup.t_data->t_ctid;
tmfd->xmax = HeapTupleHeaderGetUpdateXid(oldtup.t_data);
if (result == TM_SelfModified)
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
index 9ab7201f4de..87227d8bd2c 100644
--- a/src/include/access/tableam.h
+++ b/src/include/access/tableam.h
@@ -1479,8 +1479,8 @@ table_multi_insert(Relation rel, TupleTableSlot **slots, int nslots,
* TM_BeingModified (the last only possible if wait == false).
*
* In the failure cases, the routine fills *tmfd with the tuple's t_ctid,
- * t_xmax, and, if possible, and, if possible, t_cmax. See comments for
- * struct TM_FailureData for additional info.
+ * t_xmax, and, if possible, t_cmax. See comments for struct
+ * TM_FailureData for additional info.
*/
static inline TM_Result
table_tuple_delete(Relation rel, ItemPointer tid, CommandId cid,
diff --git a/src/test/isolation/expected/fk-snapshot.out b/src/test/isolation/expected/fk-snapshot.out
index 5faf80d6ce0..bdd26bac6cf 100644
--- a/src/test/isolation/expected/fk-snapshot.out
+++ b/src/test/isolation/expected/fk-snapshot.out
@@ -122,3 +122,25 @@ a
1
(1 row)
+
+starting permutation: s2ip2 s1brr s1ifp2 s2brr s2dp2 s1c s2c
+step s2ip2: INSERT INTO pk_noparted VALUES (2);
+step s1brr: BEGIN ISOLATION LEVEL REPEATABLE READ;
+step s1ifp2: INSERT INTO fk_parted_pk VALUES (2);
+step s2brr: BEGIN ISOLATION LEVEL REPEATABLE READ;
+step s2dp2: DELETE FROM pk_noparted WHERE a = 2; <waiting ...>
+step s1c: COMMIT;
+step s2dp2: <... completed>
+ERROR: could not serialize access due to concurrent update
+step s2c: COMMIT;
+
+starting permutation: s2ip2 s1brr s1ifn2 s2brr s2dp2 s1c s2c
+step s2ip2: INSERT INTO pk_noparted VALUES (2);
+step s1brr: BEGIN ISOLATION LEVEL REPEATABLE READ;
+step s1ifn2: INSERT INTO fk_noparted_sn VALUES (2);
+step s2brr: BEGIN ISOLATION LEVEL REPEATABLE READ;
+step s2dp2: DELETE FROM pk_noparted WHERE a = 2; <waiting ...>
+step s1c: COMMIT;
+step s2dp2: <... completed>
+ERROR: could not serialize access due to concurrent update
+step s2c: COMMIT;
diff --git a/src/test/isolation/specs/fk-snapshot.spec b/src/test/isolation/specs/fk-snapshot.spec
index 378507fbc38..9fad57e7689 100644
--- a/src/test/isolation/specs/fk-snapshot.spec
+++ b/src/test/isolation/specs/fk-snapshot.spec
@@ -13,6 +13,11 @@ setup
CREATE TABLE fk_noparted (
a int REFERENCES fk_parted_pk ON DELETE NO ACTION INITIALLY DEFERRED
);
+
+ CREATE TABLE fk_noparted_sn (
+ a int REFERENCES pk_noparted ON DELETE SET NULL
+ );
+
INSERT INTO pk_noparted VALUES (1);
INSERT INTO fk_parted_pk VALUES (1);
INSERT INTO fk_noparted VALUES (1);
@@ -20,7 +25,7 @@ setup
teardown
{
- DROP TABLE pk_noparted, fk_parted_pk, fk_noparted;
+ DROP TABLE pk_noparted, fk_parted_pk, fk_noparted, fk_noparted_sn;
}
session s1
@@ -28,6 +33,7 @@ step s1brr { BEGIN ISOLATION LEVEL REPEATABLE READ; }
step s1brc { BEGIN ISOLATION LEVEL READ COMMITTED; }
step s1ifp2 { INSERT INTO fk_parted_pk VALUES (2); }
step s1ifp1 { INSERT INTO fk_parted_pk VALUES (1); }
+step s1ifn2 { INSERT INTO fk_noparted_sn VALUES (2); }
step s1dfp { DELETE FROM fk_parted_pk WHERE a = 1; }
step s1c { COMMIT; }
step s1sfp { SELECT * FROM fk_parted_pk; }
@@ -38,6 +44,7 @@ session s2
step s2brr { BEGIN ISOLATION LEVEL REPEATABLE READ; }
step s2brc { BEGIN ISOLATION LEVEL READ COMMITTED; }
step s2ip2 { INSERT INTO pk_noparted VALUES (2); }
+step s2dp2 { DELETE FROM pk_noparted WHERE a = 2; }
step s2ifn2 { INSERT INTO fk_noparted VALUES (2); }
step s2c { COMMIT; }
step s2sfp { SELECT * FROM fk_parted_pk; }
@@ -59,3 +66,11 @@ permutation s1brc s2brc s2ip2 s1sp s2c s1sp s1ifp2 s2brc s2sfp s1c s1sfp s2ifn2
# the same no matter the snapshot mode
permutation s1brr s1dfp s1ifp1 s1c s1sfn
permutation s1brc s1dfp s1ifp1 s1c s1sfn
+
+# trying to delete a row through DELETE CASCADE, whilst that row is deleted
+# in a concurrent transaction
+permutation s2ip2 s1brr s1ifp2 s2brr s2dp2 s1c s2c
+
+# trying to update a row through DELETE SET NULL, whilst that row is deleted
+# in a concurrent transaction
+permutation s2ip2 s1brr s1ifn2 s2brr s2dp2 s1c s2c