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-rw-r--r--src/backend/storage/lmgr/predicate.c20
-rw-r--r--src/test/isolation/expected/serializable-parallel-2.out57
-rw-r--r--src/test/isolation/expected/serializable-parallel-3.out97
-rw-r--r--src/test/isolation/isolation_schedule1
-rw-r--r--src/test/isolation/specs/serializable-parallel-2.spec12
-rw-r--r--src/test/isolation/specs/serializable-parallel-3.spec47
6 files changed, 184 insertions, 50 deletions
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index d493aeef0fc..58312e19382 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -3331,6 +3331,7 @@ SetNewSxactGlobalXmin(void)
void
ReleasePredicateLocks(bool isCommit, bool isReadOnlySafe)
{
+ bool partiallyReleasing = false;
bool needToClear;
RWConflict conflict,
nextConflict,
@@ -3431,6 +3432,7 @@ ReleasePredicateLocks(bool isCommit, bool isReadOnlySafe)
else
{
MySerializableXact->flags |= SXACT_FLAG_PARTIALLY_RELEASED;
+ partiallyReleasing = true;
/* ... and proceed to perform the partial release below. */
}
}
@@ -3681,9 +3683,15 @@ ReleasePredicateLocks(bool isCommit, bool isReadOnlySafe)
* serializable transactions completes. We then find the "new oldest"
* xmin and purge any transactions which finished before this transaction
* was launched.
+ *
+ * For parallel queries in read-only transactions, it might run twice.
+ * We only release the reference on the first call.
*/
needToClear = false;
- if (TransactionIdEquals(MySerializableXact->xmin, PredXact->SxactGlobalXmin))
+ if ((partiallyReleasing ||
+ !SxactIsPartiallyReleased(MySerializableXact)) &&
+ TransactionIdEquals(MySerializableXact->xmin,
+ PredXact->SxactGlobalXmin))
{
Assert(PredXact->SxactGlobalXminCount > 0);
if (--(PredXact->SxactGlobalXminCount) == 0)
@@ -4839,10 +4847,14 @@ PreCommit_CheckForSerializationFailure(void)
LWLockAcquire(SerializableXactHashLock, LW_EXCLUSIVE);
- /* Check if someone else has already decided that we need to die */
- if (SxactIsDoomed(MySerializableXact))
+ /*
+ * Check if someone else has already decided that we need to die. Since
+ * we set our own DOOMED flag when partially releasing, ignore in that
+ * case.
+ */
+ if (SxactIsDoomed(MySerializableXact) &&
+ !SxactIsPartiallyReleased(MySerializableXact))
{
- Assert(!SxactIsPartiallyReleased(MySerializableXact));
LWLockRelease(SerializableXactHashLock);
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
diff --git a/src/test/isolation/expected/serializable-parallel-2.out b/src/test/isolation/expected/serializable-parallel-2.out
index 92753ccf39f..904fdd90806 100644
--- a/src/test/isolation/expected/serializable-parallel-2.out
+++ b/src/test/isolation/expected/serializable-parallel-2.out
@@ -1,50 +1,23 @@
Parsed test spec with 2 sessions
starting permutation: s1r s2r1 s1c s2r2 s2c
-step s1r: SELECT * FROM foo;
- a
---
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
-10
-(10 rows)
+step s1r: SELECT COUNT(*) FROM foo;
+count
+-----
+ 100
+(1 row)
-step s2r1: SELECT * FROM foo;
- a
---
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
-10
-(10 rows)
+step s2r1: SELECT COUNT(*) FROM foo;
+count
+-----
+ 100
+(1 row)
step s1c: COMMIT;
-step s2r2: SELECT * FROM foo;
- a
---
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
-10
-(10 rows)
+step s2r2: SELECT COUNT(*) FROM foo;
+count
+-----
+ 100
+(1 row)
step s2c: COMMIT;
diff --git a/src/test/isolation/expected/serializable-parallel-3.out b/src/test/isolation/expected/serializable-parallel-3.out
new file mode 100644
index 00000000000..654276a3856
--- /dev/null
+++ b/src/test/isolation/expected/serializable-parallel-3.out
@@ -0,0 +1,97 @@
+Parsed test spec with 4 sessions
+
+starting permutation: s1r s3r s2r1 s4r1 s1c s2r2 s3c s4r2 s4c s2c
+step s1r: SELECT * FROM foo;
+ a
+--
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+10
+(10 rows)
+
+step s3r: SELECT * FROM foo;
+ a
+--
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+10
+(10 rows)
+
+step s2r1: SELECT * FROM foo;
+ a
+--
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+10
+(10 rows)
+
+step s4r1: SELECT * FROM foo;
+ a
+--
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+10
+(10 rows)
+
+step s1c: COMMIT;
+step s2r2: SELECT * FROM foo;
+ a
+--
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+10
+(10 rows)
+
+step s3c: COMMIT;
+step s4r2: SELECT * FROM foo;
+ a
+--
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+10
+(10 rows)
+
+step s4c: COMMIT;
+step s2c: COMMIT;
diff --git a/src/test/isolation/isolation_schedule b/src/test/isolation/isolation_schedule
index 8e870981501..9c180a3ea9b 100644
--- a/src/test/isolation/isolation_schedule
+++ b/src/test/isolation/isolation_schedule
@@ -99,3 +99,4 @@ test: plpgsql-toast
test: truncate-conflict
test: serializable-parallel
test: serializable-parallel-2
+test: serializable-parallel-3
diff --git a/src/test/isolation/specs/serializable-parallel-2.spec b/src/test/isolation/specs/serializable-parallel-2.spec
index f3941f78631..c975d96d772 100644
--- a/src/test/isolation/specs/serializable-parallel-2.spec
+++ b/src/test/isolation/specs/serializable-parallel-2.spec
@@ -3,7 +3,8 @@
setup
{
- CREATE TABLE foo AS SELECT generate_series(1, 10)::int a;
+ CREATE TABLE foo AS SELECT generate_series(1, 100)::int a;
+ CREATE INDEX ON foo(a);
ALTER TABLE foo SET (parallel_workers = 2);
}
@@ -14,7 +15,7 @@ teardown
session s1
setup { BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE; }
-step s1r { SELECT * FROM foo; }
+step s1r { SELECT COUNT(*) FROM foo; }
step s1c { COMMIT; }
session s2
@@ -22,9 +23,12 @@ setup {
BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE READ ONLY;
SET parallel_setup_cost = 0;
SET parallel_tuple_cost = 0;
+ SET min_parallel_index_scan_size = 0;
+ SET parallel_leader_participation = off;
+ SET enable_seqscan = off;
}
-step s2r1 { SELECT * FROM foo; }
-step s2r2 { SELECT * FROM foo; }
+step s2r1 { SELECT COUNT(*) FROM foo; }
+step s2r2 { SELECT COUNT(*) FROM foo; }
step s2c { COMMIT; }
permutation s1r s2r1 s1c s2r2 s2c
diff --git a/src/test/isolation/specs/serializable-parallel-3.spec b/src/test/isolation/specs/serializable-parallel-3.spec
new file mode 100644
index 00000000000..c27298c24ff
--- /dev/null
+++ b/src/test/isolation/specs/serializable-parallel-3.spec
@@ -0,0 +1,47 @@
+# Exercise the case where a read-only serializable transaction has
+# SXACT_FLAG_RO_SAFE set in a parallel query. This variant is like
+# two copies of #2 running at the same time, and excercises the case
+# where another transaction has the same xmin, and it is the oldest.
+
+setup
+{
+ CREATE TABLE foo AS SELECT generate_series(1, 10)::int a;
+ ALTER TABLE foo SET (parallel_workers = 2);
+}
+
+teardown
+{
+ DROP TABLE foo;
+}
+
+session s1
+setup { BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE; }
+step s1r { SELECT * FROM foo; }
+step s1c { COMMIT; }
+
+session s2
+setup {
+ BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE READ ONLY;
+ SET parallel_setup_cost = 0;
+ SET parallel_tuple_cost = 0;
+ }
+step s2r1 { SELECT * FROM foo; }
+step s2r2 { SELECT * FROM foo; }
+step s2c { COMMIT; }
+
+session s3
+setup { BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE; }
+step s3r { SELECT * FROM foo; }
+step s3c { COMMIT; }
+
+session s4
+setup {
+ BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE READ ONLY;
+ SET parallel_setup_cost = 0;
+ SET parallel_tuple_cost = 0;
+ }
+step s4r1 { SELECT * FROM foo; }
+step s4r2 { SELECT * FROM foo; }
+step s4c { COMMIT; }
+
+permutation s1r s3r s2r1 s4r1 s1c s2r2 s3c s4r2 s4c s2c
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-31 07:43:03 +0000