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* [PATCH] Flag CREATE INDEX CONCURRENTLY to avoid spurious waiting
@ 2020-08-05 02:04 Alvaro Herrera <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Alvaro Herrera @ 2020-08-05 02:04 UTC (permalink / raw)
---
src/backend/commands/indexcmds.c | 13 +++++++++++--
src/include/storage/proc.h | 4 +++-
src/include/storage/procarray.h | 4 ++++
3 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index a3cb3cd47f..241c8a337e 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -393,7 +393,7 @@ WaitForOlderSnapshots(TransactionId limitXmin, bool progress)
VirtualTransactionId *old_snapshots;
old_snapshots = GetCurrentVirtualXIDs(limitXmin, true, false,
- PROC_IS_AUTOVACUUM | PROC_IN_VACUUM,
+ PROC_IS_AUTOVACUUM | PROC_IN_VACUUM | PROC_IN_CIC,
&n_old_snapshots);
if (progress)
pgstat_progress_update_param(PROGRESS_WAITFOR_TOTAL, n_old_snapshots);
@@ -413,7 +413,7 @@ WaitForOlderSnapshots(TransactionId limitXmin, bool progress)
newer_snapshots = GetCurrentVirtualXIDs(limitXmin,
true, false,
- PROC_IS_AUTOVACUUM | PROC_IN_VACUUM,
+ PROC_IS_AUTOVACUUM | PROC_IN_VACUUM | PROC_IN_CIC,
&n_newer_snapshots);
for (j = i; j < n_old_snapshots; j++)
{
@@ -1420,6 +1420,9 @@ DefineIndex(Oid relationId,
CommitTransactionCommand();
StartTransactionCommand();
+ /* Set flag for other concurrent index builds to ignore us */
+ MyPgXact->vacuumFlags |= PROC_IN_CIC;
+
/*
* The index is now visible, so we can report the OID.
*/
@@ -1482,6 +1485,9 @@ DefineIndex(Oid relationId,
CommitTransactionCommand();
StartTransactionCommand();
+ /* Set flag for other concurrent index builds to ignore us */
+ MyPgXact->vacuumFlags |= PROC_IN_CIC;
+
/*
* Phase 3 of concurrent index build
*
@@ -1541,6 +1547,9 @@ DefineIndex(Oid relationId,
CommitTransactionCommand();
StartTransactionCommand();
+ /* Set flag for other concurrent index builds to ignore us */
+ MyPgXact->vacuumFlags |= PROC_IN_CIC;
+
/* We should now definitely not be advertising any xmin. */
Assert(MyPgXact->xmin == InvalidTransactionId);
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 5ceb2494ba..b030dcde6c 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -52,6 +52,8 @@ struct XidCache
*/
#define PROC_IS_AUTOVACUUM 0x01 /* is it an autovac worker? */
#define PROC_IN_VACUUM 0x02 /* currently running lazy vacuum */
+#define PROC_IN_CIC 0x04 /* currently running CREATE INDEX
+ CONCURRENTLY */
#define PROC_VACUUM_FOR_WRAPAROUND 0x08 /* set by autovac only */
#define PROC_IN_LOGICAL_DECODING 0x10 /* currently doing logical
* decoding outside xact */
@@ -59,7 +61,7 @@ struct XidCache
/* flags reset at EOXact */
#define PROC_VACUUM_STATE_MASK \
- (PROC_IN_VACUUM | PROC_VACUUM_FOR_WRAPAROUND)
+ (PROC_IN_VACUUM | PROC_IN_CIC | PROC_VACUUM_FOR_WRAPAROUND)
/*
* We allow a small number of "weak" relation locks (AccessShareLock,
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index 01040d76e1..c6edeb36e0 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -29,17 +29,21 @@
*/
#define PROCARRAY_VACUUM_FLAG 0x02 /* currently running lazy
* vacuum */
+#define PROCARRAY_CIC_FLAG 0x04 /* currently running CREATE INDEX
+ * CONCURRENTLY */
#define PROCARRAY_LOGICAL_DECODING_FLAG 0x10 /* currently doing logical
* decoding outside xact */
#define PROCARRAY_SLOTS_XMIN 0x20 /* replication slot xmin,
* catalog_xmin */
+
/*
* Only flags in PROCARRAY_PROC_FLAGS_MASK are considered when matching
* PGXACT->vacuumFlags. Other flags are used for different purposes and
* have no corresponding PROC flag equivalent.
*/
#define PROCARRAY_PROC_FLAGS_MASK (PROCARRAY_VACUUM_FLAG | \
+ PROCARRAY_CIC_FLAG | \
PROCARRAY_LOGICAL_DECODING_FLAG)
/* Use the following flags as an input "flags" to GetOldestXmin function */
--
2.20.1
--KsGdsel6WgEHnImy--
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: BUG #17877: Referencing a system column in a foreign key leads to incorrect memory access
@ 2023-03-31 16:45 Ranier Vilela <[email protected]>
0 siblings, 1 reply; 4+ messages in thread
From: Ranier Vilela @ 2023-03-31 16:45 UTC (permalink / raw)
To: pgsql-hackers; +Cc: Tom Lane <[email protected]>; Alvaro Herrera <[email protected]>
Hi,
I think that commit f0d65c0
<https://github.com/postgres/postgres/commit/f0d65c0eaf05d6acd3ae05cde4a31465eb3992b2;
has an oversight.
Attnum == 0, is system column too, right?
All other places at tablecmds.c, has this test:
if (attnum <= 0)
ereport(ERROR,
regards,
Ranier Vilela
Attachments:
[application/octet-stream] reject_system_column_equal_zero.patch (615B, ../../CAEudQAr_71CR6w1aHNHk4T=FDvwu9YVSBubtEP3B=sik8XesKw@mail.gmail.com/3-reject_system_column_equal_zero.patch)
download | inline diff:
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7808241d3f..6e545a1d15 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -11298,7 +11298,7 @@ transformColumnNameList(Oid relId, List *colList,
errmsg("column \"%s\" referenced in foreign key constraint does not exist",
attname)));
attform = (Form_pg_attribute) GETSTRUCT(atttuple);
- if (attform->attnum < 0)
+ if (attform->attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("system columns cannot be used in foreign keys")));
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: BUG #17877: Referencing a system column in a foreign key leads to incorrect memory access
@ 2023-03-31 19:25 Tom Lane <[email protected]>
parent: Ranier Vilela <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Tom Lane @ 2023-03-31 19:25 UTC (permalink / raw)
To: Ranier Vilela <[email protected]>; +Cc: pgsql-hackers; Alvaro Herrera <[email protected]>
Ranier Vilela <[email protected]> writes:
> I think that commit f0d65c0
> <https://github.com/postgres/postgres/commit/f0d65c0eaf05d6acd3ae05cde4a31465eb3992b2;
> has an oversight.
> Attnum == 0, is system column too, right?
No, it's not valid in pg_attribute rows.
> All other places at tablecmds.c, has this test:
> if (attnum <= 0)
> ereport(ERROR,
I was actually copying this code in indexcmds.c:
if (attno < 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("index creation on system columns is not supported")));
There's really no reason to prefer one over the other in this context.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
* [PATCH v9 09/10] WIP: Make UnlockReleaseBuffer() more efficient
@ 2025-11-19 20:32 Andres Freund <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Andres Freund @ 2025-11-19 20:32 UTC (permalink / raw)
Now that the buffer content lock is implemented as part of BufferDesc.state,
releasing the lock and unpinning the buffer can be implemented as a single
atomic operation.
Author:
Reviewed-By:
Discussion: https://postgr.es/m/
Backpatch:
---
src/backend/access/nbtree/nbtpage.c | 22 +++++++++++-
src/backend/storage/buffer/bufmgr.c | 52 ++++++++++++++++++++++++++++-
2 files changed, 72 insertions(+), 2 deletions(-)
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 2ff0085b96f..073f5a05f81 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -1007,11 +1007,18 @@ _bt_relandgetbuf(Relation rel, Buffer obuf, BlockNumber blkno, int access)
Assert(BlockNumberIsValid(blkno));
if (BufferIsValid(obuf))
+ {
+ _bt_relbuf(rel, obuf);
+#if 0
+ Assert(BufferGetBlockNumber(obuf) != blkno);
_bt_unlockbuf(rel, obuf);
- buf = ReleaseAndReadBuffer(obuf, rel, blkno);
+#endif
+ }
+ buf = ReadBuffer(rel, blkno);
_bt_lockbuf(rel, buf, access);
_bt_checkpage(rel, buf);
+
return buf;
}
@@ -1023,8 +1030,21 @@ _bt_relandgetbuf(Relation rel, Buffer obuf, BlockNumber blkno, int access)
void
_bt_relbuf(Relation rel, Buffer buf)
{
+#if 0
_bt_unlockbuf(rel, buf);
ReleaseBuffer(buf);
+#else
+ /*
+ * Buffer is pinned and locked, which means that it is expected to be
+ * defined and addressable. Check that proactively.
+ */
+ VALGRIND_CHECK_MEM_IS_DEFINED(BufferGetPage(buf), BLCKSZ);
+
+ UnlockReleaseBuffer(buf);
+
+ if (!RelationUsesLocalBuffers(rel))
+ VALGRIND_MAKE_MEM_NOACCESS(BufferGetPage(buf), BLCKSZ);
+#endif
}
/*
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index e944c09fb33..647af7a167c 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -5511,13 +5511,63 @@ ReleaseBuffer(Buffer buffer)
/*
* UnlockReleaseBuffer -- release the content lock and pin on a buffer
*
- * This is just a shorthand for a common combination.
+ * This is just a, more efficient, shorthand for a common combination.
*/
void
UnlockReleaseBuffer(Buffer buffer)
{
+#if 1
+ int mode;
+ BufferDesc *buf;
+ PrivateRefCountEntry *ref;
+ uint64 sub;
+ uint64 lockstate;
+
+ if (!BufferIsValid(buffer))
+ elog(ERROR, "bad buffer ID: %d", buffer);
+
+ if (BufferIsLocal(buffer))
+ {
+ UnpinLocalBuffer(buffer);
+ return;
+ }
+
+ ResourceOwnerForgetBuffer(CurrentResourceOwner, buffer);
+
+ buf = GetBufferDescriptor(buffer - 1);
+
+ mode = BufferLockDisownInternal(buffer, buf);
+
+ /* compute state modification for lock release */
+ sub = BufferLockReleaseSub(mode);
+
+ /* compute state modification for pin release */
+ ref = GetPrivateRefCountEntry(buffer, false);
+ Assert(ref != NULL);
+ Assert(ref->data.refcount > 0);
+ ref->data.refcount--;
+
+ if (ref->data.refcount == 0)
+ {
+ sub |= BUF_REFCOUNT_ONE;
+ ForgetPrivateRefCountEntry(ref);
+ }
+
+ /* perform the lock and pin release in one atomic op */
+ lockstate = pg_atomic_sub_fetch_u64(&buf->state, sub);
+
+ /* wake up waiters etc */
+ BufferLockProcessRelease(buf, mode, lockstate);
+
+ if (lockstate & BM_PIN_COUNT_WAITER)
+ WakePinCountWaiter(buf);
+
+ RESUME_INTERRUPTS();
+
+#else
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
ReleaseBuffer(buffer);
+#endif
}
/*
--
2.48.1.76.g4e746b1a31.dirty
--rkiyqpij3ajqn7ww
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v9-0010-WIP-bufmgr-Don-t-copy-pages-while-writing-out.patch"
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2025-11-19 20:32 UTC | newest]
Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2020-08-05 02:04 [PATCH] Flag CREATE INDEX CONCURRENTLY to avoid spurious waiting Alvaro Herrera <[email protected]>
2023-03-31 16:45 Re: BUG #17877: Referencing a system column in a foreign key leads to incorrect memory access Ranier Vilela <[email protected]>
2023-03-31 19:25 ` Re: BUG #17877: Referencing a system column in a foreign key leads to incorrect memory access Tom Lane <[email protected]>
2025-11-19 20:32 [PATCH v9 09/10] WIP: Make UnlockReleaseBuffer() more efficient Andres Freund <[email protected]>
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