On Thu, Jul 04, 2024 at 03:08:16PM -0700, Noah Misch wrote:
> On Thu, Jul 04, 2024 at 08:00:00AM +0300, Alexander Lakhin wrote:
> > 28.06.2024 08:13, Noah Misch wrote:
> > > Pushed. ...
> >
> > Please look also at another anomaly, I've discovered.
> >
> > An Assert added with d5f788b41 may be falsified with:
> > CREATE TABLE t(a int PRIMARY KEY);
> > INSERT INTO t VALUES (1);
> > CREATE VIEW v AS SELECT * FROM t;
> >
> > MERGE INTO v USING (VALUES (1)) AS va(a) ON v.a = va.a
> > WHEN MATCHED THEN DO NOTHING
> > WHEN NOT MATCHED THEN DO NOTHING;
> >
> > TRAP: failed Assert("resultRelInfo->ri_TrigDesc"), File:
> > "nodeModifyTable.c", Line: 2891, PID: 1590670
>
> Thanks. When all the MERGE actions are DO NOTHING, view_has_instead_trigger()
> returns true
I've pushed the two patches for your reports. To placate cfbot, I'm attaching
the remaining patches.
Author: Noah Misch <n...@leadboat.com>
Commit: Noah Misch <n...@leadboat.com>
Warn if LOCKTAG_TUPLE is held at commit, under debug_assertions.
The current use always releases this locktag. A planned use will
continue that intent. It will involve more areas of code, making unlock
omissions easier. Warn under debug_assertions, like we do for various
resource leaks. Back-patch to v12 (all supported versions), the plan
for the commit of the new use.
Reviewed by FIXME.
Discussion: https://postgr.es/m/20240512232923.aa.nmi...@google.com
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0400a50..461d925 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -2256,6 +2256,11 @@ LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
locallock->numLockOwners = 0;
}
+#ifdef USE_ASSERT_CHECKING
+ if (LOCALLOCK_LOCKTAG(*locallock) == LOCKTAG_TUPLE && !allLocks)
+ elog(WARNING, "tuple lock held at commit");
+#endif
+
/*
* If the lock or proclock pointers are NULL, this lock was
taken via
* the relation fast-path (and is not known to have been
transferred).
Author: Noah Misch <n...@leadboat.com>
Commit: Noah Misch <n...@leadboat.com>
Fix data loss at inplace update after heap_update().
As previously-added tests demonstrated, heap_inplace_update() could
instead update an unrelated tuple of the same catalog. It could lose
the update. Losing relhasindex=t was a source of index corruption.
Inplace-updating commands like VACUUM will now wait for heap_update()
commands like GRANT TABLE and GRANT DATABASE. That isn't ideal, but a
long-running GRANT already hurts VACUUM progress more just by keeping an
XID running. The VACUUM will behave like a DELETE or UPDATE waiting for
the uncommitted change.
For implementation details, start at the heap_inplace_update_scan()
header comment and README.tuplock. Back-patch to v12 (all supported
versions). In back branches, retain a deprecated heap_inplace_update(),
for extensions.
Reviewed by FIXME and Alexander Lakhin.
Discussion:
https://postgr.es/m/CAMp+ueZQz3yDk7qg42hk6-9gxniYbp-=bg2mgqecerqr5gg...@mail.gmail.com
diff --git a/src/backend/access/heap/README.tuplock
b/src/backend/access/heap/README.tuplock
index 6441e8b..dbfa2b7 100644
--- a/src/backend/access/heap/README.tuplock
+++ b/src/backend/access/heap/README.tuplock
@@ -153,3 +153,56 @@ The following infomask bits are applicable:
We currently never set the HEAP_XMAX_COMMITTED when the HEAP_XMAX_IS_MULTI bit
is set.
+
+Locking to write inplace-updated tables
+---------------------------------------
+
+[This is the plan, but LOCKTAG_TUPLE acquisition is not yet here.]
+
+If IsInplaceUpdateRelation() returns true for a table, the table is a system
+catalog that receives heap_inplace_update_scan() calls. Preparing a
+heap_update() of these tables follows additional locking rules, to ensure we
+don't lose the effects of an inplace update. In particular, consider a moment
+when a backend has fetched the old tuple to modify, not yet having called
+heap_update(). Another backend's inplace update starting then can't conclude
+until the heap_update() places its new tuple in a buffer. We enforce that
+using locktags as follows. While DDL code is the main audience, the executor
+follows these rules to make e.g. "MERGE INTO pg_class" safer. Locking rules
+are per-catalog:
+
+ pg_class heap_inplace_update_scan() callers: before the call, acquire
+ LOCKTAG_RELATION in mode ShareLock (CREATE INDEX), ShareUpdateExclusiveLock
+ (VACUUM), or a mode with strictly more conflicts. If the update targets a
+ row of RELKIND_INDEX (but not RELKIND_PARTITIONED_INDEX), that lock must be
+ on the table. Locking the index rel is optional. (This allows VACUUM to
+ overwrite per-index pg_class while holding a lock on the table alone.) We
+ could allow weaker locks, in which case the next paragraph would simply call
+ for stronger locks for its class of commands. heap_inplace_update_scan()
+ acquires and releases LOCKTAG_TUPLE in InplaceUpdateTupleLock, an alias for
+ ExclusiveLock, on each tuple it overwrites.
+
+ pg_class heap_update() callers: before copying the tuple to modify, take a
+ lock that conflicts with at least one of those from the preceding paragraph.
+ SearchSysCacheLocked1() is one convenient way to acquire LOCKTAG_TUPLE.
+ After heap_update(), release any LOCKTAG_TUPLE. Most of these callers opt
+ to acquire just the LOCKTAG_RELATION.
+
+ pg_database: before copying the tuple to modify, all updaters of pg_database
+ rows acquire LOCKTAG_TUPLE. (Few updaters acquire LOCKTAG_OBJECT on the
+ database OID, so it wasn't worth extending that as a second option.)
+
+Ideally, DDL might want to perform permissions checks before LockTuple(), as
+we do with RangeVarGetRelidExtended() callbacks. We typically don't bother.
+LOCKTAG_TUPLE acquirers release it after each row, so the potential
+inconvenience is lower.
+
+Reading inplace-updated columns
+-------------------------------
+
+Inplace updates create an exception to the rule that tuple data won't change
+under a reader holding a pin. A reader of a heap_fetch() result tuple may
+witness a torn read. Current inplace-updated fields are aligned and are no
+wider than four bytes, and current readers don't need consistency across
+fields. Hence, they get by with just fetching each field once. XXX such a
+caller may also read a value that has not reached WAL; see
+heap_inplace_update_finish().
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 91b2014..faec28a 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -76,6 +76,9 @@ static XLogRecPtr log_heap_update(Relation reln, Buffer
oldbuf,
Buffer
newbuf, HeapTuple oldtup,
HeapTuple
newtup, HeapTuple old_key_tuple,
bool
all_visible_cleared, bool new_all_visible_cleared);
+#ifdef USE_ASSERT_CHECKING
+static void check_inplace_rel_lock(HeapTuple oldtup);
+#endif
static Bitmapset *HeapDetermineColumnsInfo(Relation relation,
Bitmapset *interesting_cols,
Bitmapset *external_cols,
@@ -97,6 +100,7 @@ static void compute_new_xmax_infomask(TransactionId xmax,
uint16 old_infomask,
static TM_Result heap_lock_updated_tuple(Relation rel, HeapTuple tuple,
ItemPointer ctid, TransactionId xid,
LockTupleMode mode);
+static bool inplace_xmax_lock(SysScanDesc scan);
static void GetMultiXactIdHintBits(MultiXactId multi, uint16 *new_infomask,
uint16
*new_infomask2);
static TransactionId MultiXactIdGetUpdateXid(TransactionId xmax,
@@ -4072,6 +4076,45 @@ l2:
return TM_Ok;
}
+#ifdef USE_ASSERT_CHECKING
+/*
+ * Confirm adequate relation lock held, per rules from README.tuplock section
+ * "Locking to write inplace-updated tables".
+ */
+static void
+check_inplace_rel_lock(HeapTuple oldtup)
+{
+ Form_pg_class classForm = (Form_pg_class) GETSTRUCT(oldtup);
+ Oid relid = classForm->oid;
+ Oid dbid;
+ LOCKTAG tag;
+
+ if (IsSharedRelation(relid))
+ dbid = InvalidOid;
+ else
+ dbid = MyDatabaseId;
+
+ if (classForm->relkind == RELKIND_INDEX)
+ {
+ Relation irel = index_open(relid, AccessShareLock);
+
+ SET_LOCKTAG_RELATION(tag, dbid, irel->rd_index->indrelid);
+ index_close(irel, AccessShareLock);
+ }
+ else
+ SET_LOCKTAG_RELATION(tag, dbid, relid);
+
+ if (!LockHeldByMe(&tag, ShareUpdateExclusiveLock, true))
+ elog(WARNING,
+ "missing lock for relation \"%s\" (OID %u, relkind %c)
@ TID (%u,%u)",
+ NameStr(classForm->relname),
+ relid,
+ classForm->relkind,
+ ItemPointerGetBlockNumber(&oldtup->t_self),
+ ItemPointerGetOffsetNumber(&oldtup->t_self));
+}
+#endif
+
/*
* Check if the specified attribute's values are the same. Subroutine for
* HeapDetermineColumnsInfo.
@@ -6041,34 +6084,45 @@ heap_abort_speculative(Relation relation, ItemPointer
tid)
}
/*
- * heap_inplace_update - update a tuple "in place" (ie, overwrite it)
+ * heap_inplace_update_scan - update a row "in place" (ie, overwrite it)
*
- * Overwriting violates both MVCC and transactional safety, so the uses
- * of this function in Postgres are extremely limited. Nonetheless we
- * find some places to use it.
+ * Overwriting violates both MVCC and transactional safety, so the uses of
+ * this function in Postgres are extremely limited. Nonetheless we find some
+ * places to use it. See README.tuplock section "Locking to write
+ * inplace-updated tables" and later sections for expectations of readers and
+ * writers of a table that gets inplace updates. Standard flow:
*
- * The tuple cannot change size, and therefore it's reasonable to assume
- * that its null bitmap (if any) doesn't change either. So we just
- * overwrite the data portion of the tuple without touching the null
- * bitmap or any of the header fields.
+ * ... [any slow preparation not requiring oldtup] ...
+ * heap_inplace_update_scan([...], &tup, &inplace_state);
+ * if (!HeapTupleIsValid(tup))
+ * elog(ERROR, [...]);
+ * ... [buffer is exclusive-locked; mutate "tup"] ...
+ * if (dirty)
+ * heap_inplace_update_finish(inplace_state, tup);
+ * else
+ * heap_inplace_update_cancel(inplace_state);
*
- * tuple is an in-memory tuple structure containing the data to be written
- * over the target tuple. Also, tuple->t_self identifies the target tuple.
+ * Since this is intended for system catalogs and SERIALIZABLE doesn't cover
+ * DDL, this skips some predicate locks.
*
- * Note that the tuple updated here had better not come directly from the
- * syscache if the relation has a toast relation as this tuple could
- * include toast values that have been expanded, causing a failure here.
+ * The first several params duplicate the systable_beginscan() param list.
+ * "oldtupcopy" is an output parameter, assigned NULL if the key ceases to
+ * find a live tuple. (In PROC_IN_VACUUM, that is a low-probability transient
+ * condition.) If "oldtupcopy" gets non-NULL, you must pass output parameter
+ * "state" to heap_inplace_update_finish() or heap_inplace_update_cancel().
*/
void
-heap_inplace_update(Relation relation, HeapTuple tuple)
+heap_inplace_update_scan(Relation relation,
+ Oid indexId,
+ bool indexOK,
+ Snapshot snapshot,
+ int nkeys, const ScanKeyData
*key,
+ HeapTuple *oldtupcopy, void
**state)
{
- Buffer buffer;
- Page page;
- OffsetNumber offnum;
- ItemId lp = NULL;
- HeapTupleHeader htup;
- uint32 oldlen;
- uint32 newlen;
+ ScanKey mutable_key = palloc(sizeof(ScanKeyData) * nkeys);
+ int retries = 0;
+ SysScanDesc scan;
+ HeapTuple oldtup;
/*
* For now, we don't allow parallel updates. Unlike a regular update,
@@ -6081,21 +6135,70 @@ heap_inplace_update(Relation relation, HeapTuple tuple)
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot update tuples during a parallel
operation")));
- INJECTION_POINT("inplace-before-pin");
- buffer = ReadBuffer(relation,
ItemPointerGetBlockNumber(&(tuple->t_self)));
- LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
- page = (Page) BufferGetPage(buffer);
+ /*
+ * Accept a snapshot argument, for symmetry, but this function advances
+ * its snapshot as needed to reach the tail of the updated tuple chain.
+ */
+ Assert(snapshot == NULL);
- offnum = ItemPointerGetOffsetNumber(&(tuple->t_self));
- if (PageGetMaxOffsetNumber(page) >= offnum)
- lp = PageGetItemId(page, offnum);
+ Assert(IsInplaceUpdateRelation(relation) ||
!IsSystemRelation(relation));
- if (PageGetMaxOffsetNumber(page) < offnum || !ItemIdIsNormal(lp))
- elog(ERROR, "invalid lp");
+ /* Loop for an exclusive-locked buffer of a non-updated tuple. */
+ do
+ {
+ CHECK_FOR_INTERRUPTS();
- htup = (HeapTupleHeader) PageGetItem(page, lp);
+ /*
+ * Processes issuing heap_update (e.g. GRANT) at maximum speed
could
+ * drive us to this error. A hostile table owner has stronger
ways to
+ * damage their own table, so that's minor.
+ */
+ if (retries++ > 10000)
+ elog(ERROR, "giving up after too many tries to
overwrite row");
- oldlen = ItemIdGetLength(lp) - htup->t_hoff;
+ memcpy(mutable_key, key, sizeof(ScanKeyData) * nkeys);
+ INJECTION_POINT("inplace-before-pin");
+ scan = systable_beginscan(relation, indexId, indexOK, snapshot,
+ nkeys,
mutable_key);
+ oldtup = systable_getnext(scan);
+ if (!HeapTupleIsValid(oldtup))
+ {
+ systable_endscan(scan);
+ *oldtupcopy = NULL;
+ return;
+ }
+
+#ifdef USE_ASSERT_CHECKING
+ if (RelationGetRelid(relation) == RelationRelationId)
+ check_inplace_rel_lock(oldtup);
+#endif
+ } while (!inplace_xmax_lock(scan));
+
+ *oldtupcopy = heap_copytuple(oldtup);
+ *state = scan;
+}
+
+/*
+ * heap_inplace_update_finish - second phase of heap_inplace_update_scan()
+ *
+ * The tuple cannot change size, and therefore its header fields and null
+ * bitmap (if any) don't change either.
+ */
+void
+heap_inplace_update_finish(void *state, HeapTuple tuple)
+{
+ SysScanDesc scan = (SysScanDesc) state;
+ TupleTableSlot *slot = scan->slot;
+ BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot;
+ HeapTuple oldtup = bslot->base.tuple;
+ HeapTupleHeader htup = oldtup->t_data;
+ Buffer buffer = bslot->buffer;
+ Relation relation = scan->heap_rel;
+ uint32 oldlen;
+ uint32 newlen;
+
+ Assert(ItemPointerEquals(&oldtup->t_self, &tuple->t_self));
+ oldlen = oldtup->t_len - htup->t_hoff;
newlen = tuple->t_len - tuple->t_data->t_hoff;
if (oldlen != newlen || htup->t_hoff != tuple->t_data->t_hoff)
elog(ERROR, "wrong tuple length");
@@ -6107,6 +6210,19 @@ heap_inplace_update(Relation relation, HeapTuple tuple)
(char *) tuple->t_data + tuple->t_data->t_hoff,
newlen);
+ /*----------
+ * XXX A crash here can allow datfrozenxid() to get ahead of
relfrozenxid:
+ *
+ * ["D" is a VACUUM (ONLY_DATABASE_STATS)]
+ * ["R" is a VACUUM tbl]
+ * D: vac_update_datfrozenid() -> systable_beginscan(pg_class)
+ * D: systable_getnext() returns pg_class tuple of tbl
+ * R: memcpy() into pg_class tuple of tbl
+ * D: raise pg_database.datfrozenxid, XLogInsert(), finish
+ * [crash]
+ * [recovery restores datfrozenxid w/o relfrozenxid]
+ */
+
MarkBufferDirty(buffer);
/* XLOG stuff */
@@ -6127,23 +6243,191 @@ heap_inplace_update(Relation relation, HeapTuple tuple)
recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_INPLACE);
- PageSetLSN(page, recptr);
+ PageSetLSN(BufferGetPage(buffer), recptr);
}
END_CRIT_SECTION();
- UnlockReleaseBuffer(buffer);
+ LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
+ systable_endscan(scan);
/*
* Send out shared cache inval if necessary. Note that because we only
* pass the new version of the tuple, this mustn't be used for any
* operations that could change catcache lookup keys. But we aren't
* bothering with index updates either, so that's true a fortiori.
+ *
+ * XXX ROLLBACK discards the invalidation. See test inplace-inval.spec.
*/
if (!IsBootstrapProcessingMode())
CacheInvalidateHeapTuple(relation, tuple, NULL);
}
+/*
+ * heap_inplace_update_cancel - abandon a heap_inplace_update_scan()
+ *
+ * This is an alternative to making a no-op update.
+ */
+void
+heap_inplace_update_cancel(void *state)
+{
+ SysScanDesc scan = (SysScanDesc) state;
+ TupleTableSlot *slot = scan->slot;
+ BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot;
+ Buffer buffer = bslot->buffer;
+
+ LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
+ systable_endscan(scan);
+}
+
+/*
+ * inplace_xmax_lock - protect inplace update from concurrent heap_update()
+ *
+ * This operates on the last tuple that systable_getnext() returned. Evaluate
+ * whether the tuple's state is compatible with a no-key update. Current
+ * transaction rowmarks are fine, as is KEY SHARE from any transaction. If
+ * compatible, return true with the buffer exclusive-locked. Otherwise,
+ * return false after blocking transactions, if any, have ended.
+ *
+ * One could modify this to return true for tuples with delete in progress,
+ * All inplace updaters take a lock that conflicts with DROP. If explicit
+ * "DELETE FROM pg_class" is in progress, we'll wait for it like we would an
+ * update.
+ *
+ * Readers of inplace-updated fields expect changes to those fields are
+ * durable. For example, vac_truncate_clog() reads datfrozenxid from
+ * pg_database tuples via catalog snapshots. A future snapshot must not
+ * return a lower datfrozenxid for the same database OID (lower in the
+ * FullTransactionIdPrecedes() sense). We achieve that since no update of a
+ * tuple can start while we hold a lock on its buffer. In cases like
+ * BEGIN;GRANT;CREATE INDEX;COMMIT we're inplace-updating a tuple visible only
+ * to this transaction. ROLLBACK then is one case where it's okay to lose
+ * inplace updates. (Restoring relhasindex=false on ROLLBACK is fine, since
+ * any concurrent CREATE INDEX would have blocked, then inplace-updated the
+ * committed tuple.)
+ *
+ * In principle, we could avoid waiting by overwriting every tuple in the
+ * updated tuple chain. Reader expectations permit updating a tuple only if
+ * it's aborted, is the tail of the chain, or we already updated the tuple
+ * referenced in its t_ctid. Hence, we would need to overwrite the tuples in
+ * order from tail to head. That would tolerate either (a) mutating all
+ * tuples in one critical section or (b) accepting a chance of partial
+ * completion. Partial completion of a relfrozenxid update would have the
+ * weird consequence that the table's next VACUUM could see the table's
+ * relfrozenxid move forward between vacuum_get_cutoffs() and finishing.
+ */
+static bool
+inplace_xmax_lock(SysScanDesc scan)
+{
+ TupleTableSlot *slot = scan->slot;
+ BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot;
+ HeapTupleData oldtup = *bslot->base.tuple;
+ Buffer buffer = bslot->buffer;
+ TM_Result result;
+ bool ret;
+
+ Assert(TTS_IS_BUFFERTUPLE(slot));
+ Assert(BufferIsValid(buffer));
+
+ LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
+
+ /*----------
+ * Interpret HeapTupleSatisfiesUpdate() like heap_update() does, except:
+ *
+ * - wait unconditionally
+ * - no tuple locks
+ * - don't recheck header after wait: simpler to defer to next iteration
+ * - don't try to continue even if the updater aborts: likewise
+ * - no crosscheck
+ */
+ result = HeapTupleSatisfiesUpdate(&oldtup, GetCurrentCommandId(false),
+
buffer);
+
+ if (result == TM_Invisible)
+ {
+ /* no known way this can happen */
+ ereport(ERROR,
+
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg_internal("attempted to overwrite
invisible tuple")));
+ }
+ else if (result == TM_SelfModified)
+ {
+ /*
+ * CREATE INDEX might reach this if an expression is silly
enough to
+ * call e.g. SELECT ... FROM pg_class FOR SHARE. C code of
other SQL
+ * statements might get here after a heap_update() of the same
row, in
+ * the absence of an intervening CommandCounterIncrement().
+ */
+ ereport(ERROR,
+
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("tuple to be updated was already
modified by an operation triggered by the current command")));
+ }
+ else if (result == TM_BeingModified)
+ {
+ TransactionId xwait;
+ uint16 infomask;
+ Relation relation;
+
+ xwait = HeapTupleHeaderGetRawXmax(oldtup.t_data);
+ infomask = oldtup.t_data->t_infomask;
+ relation = scan->heap_rel;
+
+ if (infomask & HEAP_XMAX_IS_MULTI)
+ {
+ LockTupleMode lockmode = LockTupleNoKeyExclusive;
+ MultiXactStatus mxact_status =
MultiXactStatusNoKeyUpdate;
+ int remain;
+ bool current_is_member;
+
+ if (DoesMultiXactIdConflict((MultiXactId) xwait,
infomask,
+
lockmode, ¤t_is_member))
+ {
+ LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
+ systable_endscan(scan);
+ ret = false;
+ MultiXactIdWait((MultiXactId) xwait,
mxact_status, infomask,
+ relation,
&oldtup.t_self, XLTW_Update,
+ &remain);
+ }
+ else
+ ret = true;
+ }
+ else if (TransactionIdIsCurrentTransactionId(xwait))
+ ret = true;
+ else if (HEAP_XMAX_IS_KEYSHR_LOCKED(infomask))
+ ret = true;
+ else
+ {
+ LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
+ systable_endscan(scan);
+ ret = false;
+ XactLockTableWait(xwait, relation, &oldtup.t_self,
+ XLTW_Update);
+ }
+ }
+ else
+ {
+ ret = (result == TM_Ok);
+ if (!ret)
+ {
+ LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
+ systable_endscan(scan);
+ }
+ }
+
+ /*
+ * GetCatalogSnapshot() relies on invalidation messages to know when to
+ * take a new snapshot. COMMIT of xwait is responsible for sending the
+ * invalidation. We're not acquiring heavyweight locks sufficient to
+ * block if not yet sent, so we must take a new snapshot to avoid
spinning
+ * that ends with a "too many tries" error. While we don't need this if
+ * xwait aborted, don't bother optimizing that.
+ */
+ if (!ret)
+ InvalidateCatalogSnapshot();
+ return ret;
+}
+
#define FRM_NOOP 0x0001
#define FRM_INVALIDATE_XMAX 0x0002
#define FRM_RETURN_IS_XID 0x0004
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index a819b41..b4b68b1 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2784,7 +2784,9 @@ index_update_stats(Relation rel,
{
Oid relid = RelationGetRelid(rel);
Relation pg_class;
+ ScanKeyData key[1];
HeapTuple tuple;
+ void *state;
Form_pg_class rd_rel;
bool dirty;
@@ -2818,33 +2820,12 @@ index_update_stats(Relation rel,
pg_class = table_open(RelationRelationId, RowExclusiveLock);
- /*
- * Make a copy of the tuple to update. Normally we use the syscache,
but
- * we can't rely on that during bootstrap or while reindexing pg_class
- * itself.
- */
- if (IsBootstrapProcessingMode() ||
- ReindexIsProcessingHeap(RelationRelationId))
- {
- /* don't assume syscache will work */
- TableScanDesc pg_class_scan;
- ScanKeyData key[1];
-
- ScanKeyInit(&key[0],
- Anum_pg_class_oid,
- BTEqualStrategyNumber, F_OIDEQ,
- ObjectIdGetDatum(relid));
-
- pg_class_scan = table_beginscan_catalog(pg_class, 1, key);
- tuple = heap_getnext(pg_class_scan, ForwardScanDirection);
- tuple = heap_copytuple(tuple);
- table_endscan(pg_class_scan);
- }
- else
- {
- /* normal case, use syscache */
- tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
- }
+ ScanKeyInit(&key[0],
+ Anum_pg_class_oid,
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(relid));
+ heap_inplace_update_scan(pg_class, ClassOidIndexId, true, NULL, 1, key,
+ &tuple, &state);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for relation %u", relid);
@@ -2907,11 +2888,12 @@ index_update_stats(Relation rel,
*/
if (dirty)
{
- heap_inplace_update(pg_class, tuple);
+ heap_inplace_update_finish(state, tuple);
/* the above sends a cache inval message */
}
else
{
+ heap_inplace_update_cancel(state);
/* no need to change tuple, but force relcache inval anyway */
CacheInvalidateRelcacheByTuple(tuple);
}
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 738bc46..c882f3c 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -29,6 +29,7 @@
#include "catalog/toasting.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
+#include "utils/fmgroids.h"
#include "utils/rel.h"
#include "utils/syscache.h"
@@ -333,21 +334,36 @@ create_toast_table(Relation rel, Oid toastOid, Oid
toastIndexOid,
*/
class_rel = table_open(RelationRelationId, RowExclusiveLock);
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relOid));
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "cache lookup failed for relation %u", relOid);
-
- ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
-
if (!IsBootstrapProcessingMode())
{
/* normal case, use a transactional update */
+ reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relOid));
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u",
relOid);
+
+ ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid =
toast_relid;
+
CatalogTupleUpdate(class_rel, &reltup->t_self, reltup);
}
else
{
/* While bootstrapping, we cannot UPDATE, so overwrite in-place
*/
- heap_inplace_update(class_rel, reltup);
+
+ ScanKeyData key[1];
+ void *state;
+
+ ScanKeyInit(&key[0],
+ Anum_pg_class_oid,
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(relOid));
+ heap_inplace_update_scan(class_rel, ClassOidIndexId, true,
+ NULL, 1, key,
&reltup, &state);
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "cache lookup failed for relation %u",
relOid);
+
+ ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid =
toast_relid;
+
+ heap_inplace_update_finish(state, reltup);
}
heap_freetuple(reltup);
diff --git a/src/backend/commands/dbcommands.c
b/src/backend/commands/dbcommands.c
index be629ea..da4d2b7 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -1637,6 +1637,8 @@ dropdb(const char *dbname, bool missing_ok, bool force)
bool db_istemplate;
Relation pgdbrel;
HeapTuple tup;
+ ScanKeyData key[1];
+ void *inplace_state;
Form_pg_database datform;
int notherbackends;
int npreparedxacts;
@@ -1774,11 +1776,6 @@ dropdb(const char *dbname, bool missing_ok, bool force)
*/
pgstat_drop_database(db_id);
- tup = SearchSysCacheCopy1(DATABASEOID, ObjectIdGetDatum(db_id));
- if (!HeapTupleIsValid(tup))
- elog(ERROR, "cache lookup failed for database %u", db_id);
- datform = (Form_pg_database) GETSTRUCT(tup);
-
/*
* Except for the deletion of the catalog row, subsequent actions are
not
* transactional (consider DropDatabaseBuffers() discarding modified
@@ -1790,8 +1787,17 @@ dropdb(const char *dbname, bool missing_ok, bool force)
* modification is durable before performing irreversible filesystem
* operations.
*/
+ ScanKeyInit(&key[0],
+ Anum_pg_database_oid,
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(db_id));
+ heap_inplace_update_scan(pgdbrel, DatabaseOidIndexId, true,
+ NULL, 1, key, &tup,
&inplace_state);
+ if (!HeapTupleIsValid(tup))
+ elog(ERROR, "cache lookup failed for database %u", db_id);
+ datform = (Form_pg_database) GETSTRUCT(tup);
datform->datconnlimit = DATCONNLIMIT_INVALID_DB;
- heap_inplace_update(pgdbrel, tup);
+ heap_inplace_update_finish(inplace_state, tup);
XLogFlush(XactLastRecEnd);
/*
@@ -1799,6 +1805,7 @@ dropdb(const char *dbname, bool missing_ok, bool force)
* the row will be gone, but if we fail, dropdb() can be invoked again.
*/
CatalogTupleDelete(pgdbrel, &tup->t_self);
+ heap_freetuple(tup);
/*
* Drop db-specific replication slots.
diff --git a/src/backend/commands/event_trigger.c
b/src/backend/commands/event_trigger.c
index 7a5ed6b..22d0ce7 100644
--- a/src/backend/commands/event_trigger.c
+++ b/src/backend/commands/event_trigger.c
@@ -946,25 +946,18 @@ EventTriggerOnLogin(void)
{
Relation pg_db = table_open(DatabaseRelationId,
RowExclusiveLock);
HeapTuple tuple;
+ void *state;
Form_pg_database db;
ScanKeyData key[1];
- SysScanDesc scan;
- /*
- * Get the pg_database tuple to scribble on. Note that
this does
- * not directly rely on the syscache to avoid issues
with
- * flattened toast values for the in-place update.
- */
+ /* Fetch a copy of the tuple to scribble on */
ScanKeyInit(&key[0],
Anum_pg_database_oid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(MyDatabaseId));
- scan = systable_beginscan(pg_db, DatabaseOidIndexId,
true,
- NULL,
1, key);
- tuple = systable_getnext(scan);
- tuple = heap_copytuple(tuple);
- systable_endscan(scan);
+ heap_inplace_update_scan(pg_db, DatabaseOidIndexId,
true,
+ NULL,
1, key, &tuple, &state);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for database
%u", MyDatabaseId);
@@ -980,13 +973,15 @@ EventTriggerOnLogin(void)
* that avoids possible waiting on the
row-level lock. Second,
* that avoids dealing with TOAST.
*
- * It's known that changes made by
heap_inplace_update() may
- * be lost due to concurrent normal updates.
However, we are
- * OK with that. The subsequent connections
will still have a
- * chance to set "dathasloginevt" to false.
+ * Changes made by inplace update may be lost
due to
+ * concurrent normal updates; see
inplace-inval.spec. However,
+ * we are OK with that. The subsequent
connections will still
+ * have a chance to set "dathasloginevt" to
false.
*/
- heap_inplace_update(pg_db, tuple);
+ heap_inplace_update_finish(state, tuple);
}
+ else
+ heap_inplace_update_cancel(state);
table_close(pg_db, RowExclusiveLock);
heap_freetuple(tuple);
}
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 48f8eab..d299a25 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -1405,7 +1405,9 @@ vac_update_relstats(Relation relation,
{
Oid relid = RelationGetRelid(relation);
Relation rd;
+ ScanKeyData key[1];
HeapTuple ctup;
+ void *inplace_state;
Form_pg_class pgcform;
bool dirty,
futurexid,
@@ -1416,7 +1418,12 @@ vac_update_relstats(Relation relation,
rd = table_open(RelationRelationId, RowExclusiveLock);
/* Fetch a copy of the tuple to scribble on */
- ctup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
+ ScanKeyInit(&key[0],
+ Anum_pg_class_oid,
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(relid));
+ heap_inplace_update_scan(rd, ClassOidIndexId, true,
+ NULL, 1, key, &ctup,
&inplace_state);
if (!HeapTupleIsValid(ctup))
elog(ERROR, "pg_class entry for relid %u vanished during
vacuuming",
relid);
@@ -1524,7 +1531,9 @@ vac_update_relstats(Relation relation,
/* If anything changed, write out the tuple. */
if (dirty)
- heap_inplace_update(rd, ctup);
+ heap_inplace_update_finish(inplace_state, ctup);
+ else
+ heap_inplace_update_cancel(inplace_state);
table_close(rd, RowExclusiveLock);
@@ -1576,6 +1585,7 @@ vac_update_datfrozenxid(void)
bool bogus = false;
bool dirty = false;
ScanKeyData key[1];
+ void *inplace_state;
/*
* Restrict this task to one backend per database. This avoids race
@@ -1699,20 +1709,18 @@ vac_update_datfrozenxid(void)
relation = table_open(DatabaseRelationId, RowExclusiveLock);
/*
- * Get the pg_database tuple to scribble on. Note that this does not
- * directly rely on the syscache to avoid issues with flattened toast
- * values for the in-place update.
+ * Fetch a copy of the tuple to scribble on. We could check the
syscache
+ * tuple first. If that concluded !dirty, we'd avoid waiting on
+ * concurrent heap_update() and would avoid exclusive-locking the
buffer.
+ * For now, don't optimize that.
*/
ScanKeyInit(&key[0],
Anum_pg_database_oid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(MyDatabaseId));
- scan = systable_beginscan(relation, DatabaseOidIndexId, true,
- NULL, 1, key);
- tuple = systable_getnext(scan);
- tuple = heap_copytuple(tuple);
- systable_endscan(scan);
+ heap_inplace_update_scan(relation, DatabaseOidIndexId, true,
+ NULL, 1, key, &tuple,
&inplace_state);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for database %u",
MyDatabaseId);
@@ -1746,7 +1754,9 @@ vac_update_datfrozenxid(void)
newMinMulti = dbform->datminmxid;
if (dirty)
- heap_inplace_update(relation, tuple);
+ heap_inplace_update_finish(inplace_state, tuple);
+ else
+ heap_inplace_update_cancel(inplace_state);
heap_freetuple(tuple);
table_close(relation, RowExclusiveLock);
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 9e9aec8..2e13fb9 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -336,7 +336,14 @@ extern TM_Result heap_lock_tuple(Relation relation,
HeapTuple tuple,
bool
follow_updates,
Buffer
*buffer, struct TM_FailureData *tmfd);
-extern void heap_inplace_update(Relation relation, HeapTuple tuple);
+extern void heap_inplace_update_scan(Relation relation,
+ Oid
indexId,
+ bool
indexOK,
+
Snapshot snapshot,
+ int
nkeys, const ScanKeyData *key,
+
HeapTuple *oldtupcopy, void **state);
+extern void heap_inplace_update_finish(void *state, HeapTuple tuple);
+extern void heap_inplace_update_cancel(void *state);
extern bool heap_prepare_freeze_tuple(HeapTupleHeader tuple,
const
struct VacuumCutoffs *cutoffs,
HeapPageFreeze *pagefrz,
diff --git a/src/test/isolation/expected/intra-grant-inplace-db.out
b/src/test/isolation/expected/intra-grant-inplace-db.out
index 432ece5..a91402c 100644
--- a/src/test/isolation/expected/intra-grant-inplace-db.out
+++ b/src/test/isolation/expected/intra-grant-inplace-db.out
@@ -9,20 +9,20 @@ step b1: BEGIN;
step grant1:
GRANT TEMP ON DATABASE isolation_regression TO regress_temp_grantee;
-step vac2: VACUUM (FREEZE);
+step vac2: VACUUM (FREEZE); <waiting ...>
step snap3:
INSERT INTO frozen_witness
SELECT datfrozenxid FROM pg_database WHERE datname = current_catalog;
step c1: COMMIT;
+step vac2: <... completed>
step cmp3:
SELECT 'datfrozenxid retreated'
FROM pg_database
WHERE datname = current_catalog
AND age(datfrozenxid) > (SELECT min(age(x)) FROM
frozen_witness);
-?column?
-----------------------
-datfrozenxid retreated
-(1 row)
+?column?
+--------
+(0 rows)
diff --git a/src/test/isolation/expected/intra-grant-inplace.out
b/src/test/isolation/expected/intra-grant-inplace.out
index cc1e47a..c2a9841 100644
--- a/src/test/isolation/expected/intra-grant-inplace.out
+++ b/src/test/isolation/expected/intra-grant-inplace.out
@@ -14,15 +14,16 @@ relhasindex
f
(1 row)
-step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c);
+step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c); <waiting ...>
step c1: COMMIT;
+step addk2: <... completed>
step read2:
SELECT relhasindex FROM pg_class
WHERE oid = 'intra_grant_inplace'::regclass;
relhasindex
-----------
-f
+t
(1 row)
@@ -58,8 +59,9 @@ relhasindex
f
(1 row)
-step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c);
+step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c); <waiting ...>
step r3: ROLLBACK;
+step addk2: <... completed>
starting permutation: b2 sfnku2 addk2 c2
step b2: BEGIN;
@@ -122,17 +124,18 @@ relhasindex
f
(1 row)
-step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c);
+step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c); <waiting ...>
step r3: ROLLBACK;
step grant1: <... completed>
step c1: COMMIT;
+step addk2: <... completed>
step read2:
SELECT relhasindex FROM pg_class
WHERE oid = 'intra_grant_inplace'::regclass;
relhasindex
-----------
-f
+t
(1 row)
diff --git a/src/test/isolation/specs/intra-grant-inplace-db.spec
b/src/test/isolation/specs/intra-grant-inplace-db.spec
index bbecd5d..9de40ec 100644
--- a/src/test/isolation/specs/intra-grant-inplace-db.spec
+++ b/src/test/isolation/specs/intra-grant-inplace-db.spec
@@ -42,5 +42,4 @@ step cmp3 {
}
-# XXX extant bug
permutation snap3 b1 grant1 vac2(c1) snap3 c1 cmp3
diff --git a/src/test/isolation/specs/intra-grant-inplace.spec
b/src/test/isolation/specs/intra-grant-inplace.spec
index 3cd696b..eed0b52 100644
--- a/src/test/isolation/specs/intra-grant-inplace.spec
+++ b/src/test/isolation/specs/intra-grant-inplace.spec
@@ -73,7 +73,7 @@ step keyshr5 {
teardown { ROLLBACK; }
-# XXX extant bugs: permutation comments refer to planned post-bugfix behavior
+# XXX extant bugs: permutation comments refer to planned future LockTuple()
permutation
b1
diff --git a/src/test/modules/injection_points/expected/inplace.out
b/src/test/modules/injection_points/expected/inplace.out
index 123f45a..db7dab6 100644
--- a/src/test/modules/injection_points/expected/inplace.out
+++ b/src/test/modules/injection_points/expected/inplace.out
@@ -40,4 +40,301 @@ step read1:
SELECT reltuples = -1 AS reltuples_unknown
FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
-ERROR: could not create unique index "pg_class_oid_index"
+reltuples_unknown
+-----------------
+f
+(1 row)
+
+
+starting permutation: begin2 grant2 vac1 c2 vac3 mkrels3 read1
+mkrels
+------
+
+(1 row)
+
+injection_points_attach
+-----------------------
+
+(1 row)
+
+step begin2: BEGIN;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step vac1: VACUUM vactest.orig50; -- wait during inplace update <waiting ...>
+step c2: COMMIT;
+step vac3: VACUUM pg_class;
+step mkrels3:
+ SELECT vactest.mkrels('intruder', 1, 100); -- repopulate LP_UNUSED
+ SELECT injection_points_detach('inplace-before-pin');
+ SELECT injection_points_wakeup('inplace-before-pin');
+
+mkrels
+------
+
+(1 row)
+
+injection_points_detach
+-----------------------
+
+(1 row)
+
+injection_points_wakeup
+-----------------------
+
+(1 row)
+
+step vac1: <... completed>
+step read1:
+ REINDEX TABLE pg_class; -- look for duplicates
+ SELECT reltuples = -1 AS reltuples_unknown
+ FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
+
+reltuples_unknown
+-----------------
+f
+(1 row)
+
+
+starting permutation: begin2 grant2 vac1 r2 vac3 mkrels3 read1
+mkrels
+------
+
+(1 row)
+
+injection_points_attach
+-----------------------
+
+(1 row)
+
+step begin2: BEGIN;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step vac1: VACUUM vactest.orig50; -- wait during inplace update <waiting ...>
+step r2: ROLLBACK;
+step vac3: VACUUM pg_class;
+step mkrels3:
+ SELECT vactest.mkrels('intruder', 1, 100); -- repopulate LP_UNUSED
+ SELECT injection_points_detach('inplace-before-pin');
+ SELECT injection_points_wakeup('inplace-before-pin');
+
+mkrels
+------
+
+(1 row)
+
+injection_points_detach
+-----------------------
+
+(1 row)
+
+injection_points_wakeup
+-----------------------
+
+(1 row)
+
+step vac1: <... completed>
+step read1:
+ REINDEX TABLE pg_class; -- look for duplicates
+ SELECT reltuples = -1 AS reltuples_unknown
+ FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
+
+reltuples_unknown
+-----------------
+f
+(1 row)
+
+
+starting permutation: begin2 grant2 vac1 c2 revoke2 grant2 vac3 mkrels3 read1
+mkrels
+------
+
+(1 row)
+
+injection_points_attach
+-----------------------
+
+(1 row)
+
+step begin2: BEGIN;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step vac1: VACUUM vactest.orig50; -- wait during inplace update <waiting ...>
+step c2: COMMIT;
+step revoke2: REVOKE SELECT ON TABLE vactest.orig50 FROM PUBLIC;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step vac3: VACUUM pg_class;
+step mkrels3:
+ SELECT vactest.mkrels('intruder', 1, 100); -- repopulate LP_UNUSED
+ SELECT injection_points_detach('inplace-before-pin');
+ SELECT injection_points_wakeup('inplace-before-pin');
+
+mkrels
+------
+
+(1 row)
+
+injection_points_detach
+-----------------------
+
+(1 row)
+
+injection_points_wakeup
+-----------------------
+
+(1 row)
+
+step vac1: <... completed>
+step read1:
+ REINDEX TABLE pg_class; -- look for duplicates
+ SELECT reltuples = -1 AS reltuples_unknown
+ FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
+
+reltuples_unknown
+-----------------
+f
+(1 row)
+
+
+starting permutation: vac1 begin2 grant2 revoke2 mkrels3 c2 read1
+mkrels
+------
+
+(1 row)
+
+injection_points_attach
+-----------------------
+
+(1 row)
+
+step vac1: VACUUM vactest.orig50; -- wait during inplace update <waiting ...>
+step begin2: BEGIN;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step revoke2: REVOKE SELECT ON TABLE vactest.orig50 FROM PUBLIC;
+step mkrels3:
+ SELECT vactest.mkrels('intruder', 1, 100); -- repopulate LP_UNUSED
+ SELECT injection_points_detach('inplace-before-pin');
+ SELECT injection_points_wakeup('inplace-before-pin');
+
+mkrels
+------
+
+(1 row)
+
+injection_points_detach
+-----------------------
+
+(1 row)
+
+injection_points_wakeup
+-----------------------
+
+(1 row)
+
+step c2: COMMIT;
+step vac1: <... completed>
+step read1:
+ REINDEX TABLE pg_class; -- look for duplicates
+ SELECT reltuples = -1 AS reltuples_unknown
+ FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
+
+reltuples_unknown
+-----------------
+f
+(1 row)
+
+
+starting permutation: begin2 grant2 vac1 r2 grant2 revoke2 vac3 mkrels3 read1
+mkrels
+------
+
+(1 row)
+
+injection_points_attach
+-----------------------
+
+(1 row)
+
+step begin2: BEGIN;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step vac1: VACUUM vactest.orig50; -- wait during inplace update <waiting ...>
+step r2: ROLLBACK;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step revoke2: REVOKE SELECT ON TABLE vactest.orig50 FROM PUBLIC;
+step vac3: VACUUM pg_class;
+step mkrels3:
+ SELECT vactest.mkrels('intruder', 1, 100); -- repopulate LP_UNUSED
+ SELECT injection_points_detach('inplace-before-pin');
+ SELECT injection_points_wakeup('inplace-before-pin');
+
+mkrels
+------
+
+(1 row)
+
+injection_points_detach
+-----------------------
+
+(1 row)
+
+injection_points_wakeup
+-----------------------
+
+(1 row)
+
+step vac1: <... completed>
+step read1:
+ REINDEX TABLE pg_class; -- look for duplicates
+ SELECT reltuples = -1 AS reltuples_unknown
+ FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
+
+reltuples_unknown
+-----------------
+f
+(1 row)
+
+
+starting permutation: begin2 grant2 vac1 c2 revoke2 vac3 mkrels3 read1
+mkrels
+------
+
+(1 row)
+
+injection_points_attach
+-----------------------
+
+(1 row)
+
+step begin2: BEGIN;
+step grant2: GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC;
+step vac1: VACUUM vactest.orig50; -- wait during inplace update <waiting ...>
+step c2: COMMIT;
+step revoke2: REVOKE SELECT ON TABLE vactest.orig50 FROM PUBLIC;
+step vac3: VACUUM pg_class;
+step mkrels3:
+ SELECT vactest.mkrels('intruder', 1, 100); -- repopulate LP_UNUSED
+ SELECT injection_points_detach('inplace-before-pin');
+ SELECT injection_points_wakeup('inplace-before-pin');
+
+mkrels
+------
+
+(1 row)
+
+injection_points_detach
+-----------------------
+
+(1 row)
+
+injection_points_wakeup
+-----------------------
+
+(1 row)
+
+step vac1: <... completed>
+step read1:
+ REINDEX TABLE pg_class; -- look for duplicates
+ SELECT reltuples = -1 AS reltuples_unknown
+ FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
+
+reltuples_unknown
+-----------------
+f
+(1 row)
+
diff --git a/src/test/modules/injection_points/specs/inplace.spec
b/src/test/modules/injection_points/specs/inplace.spec
index e957713..86539a5 100644
--- a/src/test/modules/injection_points/specs/inplace.spec
+++ b/src/test/modules/injection_points/specs/inplace.spec
@@ -32,12 +32,9 @@ setup
CREATE TABLE vactest.orig50 ();
SELECT vactest.mkrels('orig', 51, 100);
}
-
-# XXX DROP causes an assertion failure; adopt DROP once fixed
teardown
{
- --DROP SCHEMA vactest CASCADE;
- DO $$BEGIN EXECUTE 'ALTER SCHEMA vactest RENAME TO schema' || oid FROM
pg_namespace where nspname = 'vactest'; END$$;
+ DROP SCHEMA vactest CASCADE;
DROP EXTENSION injection_points;
}
@@ -56,11 +53,13 @@ step read1 {
FROM pg_class WHERE oid = 'vactest.orig50'::regclass;
}
-
# Transactional updates of the tuple vac1 is waiting to inplace-update.
session s2
step grant2 { GRANT SELECT ON TABLE vactest.orig50 TO PUBLIC; }
-
+step revoke2 { REVOKE SELECT ON TABLE vactest.orig50 FROM PUBLIC; }
+step begin2 { BEGIN; }
+step c2 { COMMIT; }
+step r2 { ROLLBACK; }
# Non-blocking actions.
session s3
@@ -74,10 +73,69 @@ step mkrels3 {
}
-# XXX extant bug
+# target gains a successor at the last moment
permutation
vac1(mkrels3) # reads pg_class tuple T0 for vactest.orig50, xmax
invalid
grant2 # T0 becomes eligible for pruning, T1 is
successor
vac3 # T0 becomes LP_UNUSED
- mkrels3 # T0 reused; vac1 wakes and overwrites the
reused T0
+ mkrels3 # vac1 wakes, scans to T1
read1
+
+# target already has a successor, which commits
+permutation
+ begin2
+ grant2 # T0.t_ctid = T1
+ vac1(mkrels3) # reads T0 for vactest.orig50
+ c2 # T0 becomes eligible for pruning
+ vac3 # T0 becomes LP_UNUSED
+ mkrels3 # vac1 wakes, scans to T1
+ read1
+
+# target already has a successor, which becomes LP_UNUSED at the last moment
+permutation
+ begin2
+ grant2 # T0.t_ctid = T1
+ vac1(mkrels3) # reads T0 for vactest.orig50
+ r2 # T1 becomes eligible for pruning
+ vac3 # T1 becomes LP_UNUSED
+ mkrels3 # reuse T1; vac1 scans to T0
+ read1
+
+# target already has a successor, which becomes LP_REDIRECT at the last moment
+permutation
+ begin2
+ grant2 # T0.t_ctid = T1, non-HOT due to filled page
+ vac1(mkrels3) # reads T0
+ c2
+ revoke2 # HOT update to T2
+ grant2 # HOT update to T3
+ vac3 # T1 becomes LP_REDIRECT
+ mkrels3 # reuse T2; vac1 scans to T3
+ read1
+
+# waiting for updater to end
+permutation
+ vac1(c2) # reads pg_class tuple T0 for vactest.orig50,
xmax invalid
+ begin2
+ grant2 # T0.t_ctid = T1, non-HOT due to filled page
+ revoke2 # HOT update to T2
+ mkrels3 # vac1 awakes briefly, then waits for s2
+ c2
+ read1
+
+# Another LP_UNUSED. This time, do change the live tuple. Final live tuple
+# body is identical to original, at a different TID.
+permutation
+ begin2
+ grant2 # T0.t_ctid = T1, non-HOT due to filled page
+ vac1(mkrels3) # reads T0
+ r2 # T1 becomes eligible for pruning
+ grant2 # T0.t_ctid = T2; T0 becomes eligible for
pruning
+ revoke2 # T2.t_ctid = T3; T2 becomes eligible for
pruning
+ vac3 # T0, T1 & T2 become LP_UNUSED
+ mkrels3 # reuse T0, T1 & T2; vac1 scans to T3
+ read1
+
+# Another LP_REDIRECT. Compared to the earlier test, omit the last grant2.
+# Hence, final live tuple body is identical to original, at a different TID.
+permutation begin2 grant2 vac1(mkrels3) c2 revoke2 vac3 mkrels3 read1
Author: Noah Misch <n...@leadboat.com>
Commit: Noah Misch <n...@leadboat.com>
Make heap_update() callers wait for inplace update.
The previous commit fixed some ways of losing an inplace update. It
remained possible to lose one when a backend working toward a
heap_update() copied a tuple into memory just before inplace update of
that tuple. In catalogs eligible for inplace update, use LOCKTAG_TUPLE
to govern admission to the steps of copying an old tuple, modifying it,
and issuing heap_update(). This includes UPDATE and MERGE commands. To
avoid changing most of the pg_class DDL, don't require LOCKTAG_TUPLE
when holding a relation lock sufficient to exclude inplace updaters.
Back-patch to v12 (all supported versions).
Reviewed by FIXME.
Discussion: https://postgr.es/m/20231027214946.79.nmi...@google.com
diff --git a/src/backend/access/heap/README.tuplock
b/src/backend/access/heap/README.tuplock
index dbfa2b7..fb06ff2 100644
--- a/src/backend/access/heap/README.tuplock
+++ b/src/backend/access/heap/README.tuplock
@@ -157,8 +157,6 @@ is set.
Locking to write inplace-updated tables
---------------------------------------
-[This is the plan, but LOCKTAG_TUPLE acquisition is not yet here.]
-
If IsInplaceUpdateRelation() returns true for a table, the table is a system
catalog that receives heap_inplace_update_scan() calls. Preparing a
heap_update() of these tables follows additional locking rules, to ensure we
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index faec28a..051aa10 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -51,6 +51,8 @@
#include "access/xloginsert.h"
#include "access/xlogutils.h"
#include "catalog/catalog.h"
+#include "catalog/pg_database.h"
+#include "catalog/pg_database_d.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "pgstat.h"
@@ -77,6 +79,9 @@ static XLogRecPtr log_heap_update(Relation reln, Buffer
oldbuf,
HeapTuple
newtup, HeapTuple old_key_tuple,
bool
all_visible_cleared, bool new_all_visible_cleared);
#ifdef USE_ASSERT_CHECKING
+static void check_lock_if_inplace_updateable_rel(Relation relation,
+
ItemPointer otid,
+
HeapTuple newtup);
static void check_inplace_rel_lock(HeapTuple oldtup);
#endif
static Bitmapset *HeapDetermineColumnsInfo(Relation relation,
@@ -126,6 +131,8 @@ static HeapTuple ExtractReplicaIdentity(Relation relation,
HeapTuple tp, bool ke
* heavyweight lock mode and MultiXactStatus values to use for any particular
* tuple lock strength.
*
+ * These interact with InplaceUpdateTupleLock, an alias for ExclusiveLock.
+ *
* Don't look at lockstatus/updstatus directly! Use get_mxact_status_for_lock
* instead.
*/
@@ -3212,6 +3219,10 @@ heap_update(Relation relation, ItemPointer otid,
HeapTuple newtup,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot update tuples during a parallel
operation")));
+#ifdef USE_ASSERT_CHECKING
+ check_lock_if_inplace_updateable_rel(relation, otid, newtup);
+#endif
+
/*
* Fetch the list of attributes to be checked for various operations.
*
@@ -4078,6 +4089,89 @@ l2:
#ifdef USE_ASSERT_CHECKING
/*
+ * Confirm adequate lock held during heap_update(), per rules from
+ * README.tuplock section "Locking to write inplace-updated tables".
+ */
+static void
+check_lock_if_inplace_updateable_rel(Relation relation,
+
ItemPointer otid,
+
HeapTuple newtup)
+{
+ /* LOCKTAG_TUPLE acceptable for any catalog */
+ switch (RelationGetRelid(relation))
+ {
+ case RelationRelationId:
+ case DatabaseRelationId:
+ {
+ LOCKTAG tuptag;
+
+ SET_LOCKTAG_TUPLE(tuptag,
+
relation->rd_lockInfo.lockRelId.dbId,
+
relation->rd_lockInfo.lockRelId.relId,
+
ItemPointerGetBlockNumber(otid),
+
ItemPointerGetOffsetNumber(otid));
+ if (LockHeldByMe(&tuptag,
InplaceUpdateTupleLock, false))
+ return;
+ }
+ break;
+ default:
+ Assert(!IsInplaceUpdateRelation(relation));
+ return;
+ }
+
+ switch (RelationGetRelid(relation))
+ {
+ case RelationRelationId:
+ {
+ /* LOCKTAG_TUPLE or LOCKTAG_RELATION ok */
+ Form_pg_class classForm = (Form_pg_class)
GETSTRUCT(newtup);
+ Oid relid = classForm->oid;
+ Oid dbid;
+ LOCKTAG tag;
+
+ if (IsSharedRelation(relid))
+ dbid = InvalidOid;
+ else
+ dbid = MyDatabaseId;
+
+ if (classForm->relkind == RELKIND_INDEX)
+ {
+ Relation irel =
index_open(relid, AccessShareLock);
+
+ SET_LOCKTAG_RELATION(tag, dbid,
irel->rd_index->indrelid);
+ index_close(irel, AccessShareLock);
+ }
+ else
+ SET_LOCKTAG_RELATION(tag, dbid, relid);
+
+ if (!LockHeldByMe(&tag,
ShareUpdateExclusiveLock, false) &&
+ !LockHeldByMe(&tag,
ShareRowExclusiveLock, true))
+ elog(WARNING,
+ "missing lock for relation
\"%s\" (OID %u, relkind %c) @ TID (%u,%u)",
+ NameStr(classForm->relname),
+ relid,
+ classForm->relkind,
+
ItemPointerGetBlockNumber(otid),
+
ItemPointerGetOffsetNumber(otid));
+ }
+ break;
+ case DatabaseRelationId:
+ {
+ /* LOCKTAG_TUPLE required */
+ Form_pg_database dbForm = (Form_pg_database)
GETSTRUCT(newtup);
+
+ elog(WARNING,
+ "missing lock on database \"%s\" (OID
%u) @ TID (%u,%u)",
+ NameStr(dbForm->datname),
+ dbForm->oid,
+ ItemPointerGetBlockNumber(otid),
+ ItemPointerGetOffsetNumber(otid));
+ }
+ break;
+ }
+}
+
+/*
* Confirm adequate relation lock held, per rules from README.tuplock section
* "Locking to write inplace-updated tables".
*/
@@ -6123,6 +6217,7 @@ heap_inplace_update_scan(Relation relation,
int retries = 0;
SysScanDesc scan;
HeapTuple oldtup;
+ ItemPointerData locked;
/*
* For now, we don't allow parallel updates. Unlike a regular update,
@@ -6144,6 +6239,7 @@ heap_inplace_update_scan(Relation relation,
Assert(IsInplaceUpdateRelation(relation) ||
!IsSystemRelation(relation));
/* Loop for an exclusive-locked buffer of a non-updated tuple. */
+ ItemPointerSetInvalid(&locked);
do
{
CHECK_FOR_INTERRUPTS();
@@ -6163,6 +6259,8 @@ heap_inplace_update_scan(Relation relation,
oldtup = systable_getnext(scan);
if (!HeapTupleIsValid(oldtup))
{
+ if (ItemPointerIsValid(&locked))
+ UnlockTuple(relation, &locked,
InplaceUpdateTupleLock);
systable_endscan(scan);
*oldtupcopy = NULL;
return;
@@ -6172,6 +6270,15 @@ heap_inplace_update_scan(Relation relation,
if (RelationGetRelid(relation) == RelationRelationId)
check_inplace_rel_lock(oldtup);
#endif
+
+ if (!(ItemPointerIsValid(&locked) &&
+ ItemPointerEquals(&locked, &oldtup->t_self)))
+ {
+ if (ItemPointerIsValid(&locked))
+ UnlockTuple(relation, &locked,
InplaceUpdateTupleLock);
+ LockTuple(relation, &oldtup->t_self,
InplaceUpdateTupleLock);
+ }
+ locked = oldtup->t_self;
} while (!inplace_xmax_lock(scan));
*oldtupcopy = heap_copytuple(oldtup);
@@ -6183,6 +6290,8 @@ heap_inplace_update_scan(Relation relation,
*
* The tuple cannot change size, and therefore its header fields and null
* bitmap (if any) don't change either.
+ *
+ * Since we hold LOCKTAG_TUPLE, no updater has a local copy of this tuple.
*/
void
heap_inplace_update_finish(void *state, HeapTuple tuple)
@@ -6249,6 +6358,7 @@ heap_inplace_update_finish(void *state, HeapTuple tuple)
END_CRIT_SECTION();
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
+ UnlockTuple(relation, &tuple->t_self, InplaceUpdateTupleLock);
systable_endscan(scan);
/*
@@ -6274,9 +6384,12 @@ heap_inplace_update_cancel(void *state)
SysScanDesc scan = (SysScanDesc) state;
TupleTableSlot *slot = scan->slot;
BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot;
+ HeapTuple oldtup = bslot->base.tuple;
Buffer buffer = bslot->buffer;
+ Relation relation = scan->heap_rel;
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
+ UnlockTuple(relation, &oldtup->t_self, InplaceUpdateTupleLock);
systable_endscan(scan);
}
@@ -6335,7 +6448,7 @@ inplace_xmax_lock(SysScanDesc scan)
* Interpret HeapTupleSatisfiesUpdate() like heap_update() does, except:
*
* - wait unconditionally
- * - no tuple locks
+ * - caller handles tuple lock, since inplace needs it unconditionally
* - don't recheck header after wait: simpler to defer to next iteration
* - don't try to continue even if the updater aborts: likewise
* - no crosscheck
diff --git a/src/backend/catalog/aclchk.c b/src/backend/catalog/aclchk.c
index a44ccee..bc0e259 100644
--- a/src/backend/catalog/aclchk.c
+++ b/src/backend/catalog/aclchk.c
@@ -75,6 +75,7 @@
#include "nodes/makefuncs.h"
#include "parser/parse_func.h"
#include "parser/parse_type.h"
+#include "storage/lmgr.h"
#include "utils/acl.h"
#include "utils/aclchk_internal.h"
#include "utils/builtins.h"
@@ -1848,7 +1849,7 @@ ExecGrant_Relation(InternalGrant *istmt)
HeapTuple tuple;
ListCell *cell_colprivs;
- tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relOid));
+ tuple = SearchSysCacheLocked1(RELOID, ObjectIdGetDatum(relOid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u",
relOid);
pg_class_tuple = (Form_pg_class) GETSTRUCT(tuple);
@@ -2060,6 +2061,7 @@ ExecGrant_Relation(InternalGrant *istmt)
values, nulls, replaces);
CatalogTupleUpdate(relation, &newtuple->t_self,
newtuple);
+ UnlockTuple(relation, &tuple->t_self,
InplaceUpdateTupleLock);
/* Update initial privileges for extensions */
recordExtensionInitPriv(relOid, RelationRelationId, 0,
new_acl);
@@ -2072,6 +2074,8 @@ ExecGrant_Relation(InternalGrant *istmt)
pfree(new_acl);
}
+ else
+ UnlockTuple(relation, &tuple->t_self,
InplaceUpdateTupleLock);
/*
* Handle column-level privileges, if any were specified or
implied.
@@ -2185,7 +2189,7 @@ ExecGrant_common(InternalGrant *istmt, Oid classid,
AclMode default_privs,
Oid *oldmembers;
Oid *newmembers;
- tuple = SearchSysCache1(cacheid, ObjectIdGetDatum(objectid));
+ tuple = SearchSysCacheLocked1(cacheid,
ObjectIdGetDatum(objectid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for %s %u",
get_object_class_descr(classid), objectid);
@@ -2261,6 +2265,7 @@ ExecGrant_common(InternalGrant *istmt, Oid classid,
AclMode default_privs,
nulls,
replaces);
CatalogTupleUpdate(relation, &newtuple->t_self, newtuple);
+ UnlockTuple(relation, &tuple->t_self, InplaceUpdateTupleLock);
/* Update initial privileges for extensions */
recordExtensionInitPriv(objectid, classid, 0, new_acl);
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 6c39434..8aefbcd 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -138,6 +138,15 @@ IsCatalogRelationOid(Oid relid)
/*
* IsInplaceUpdateRelation
* True iff core code performs inplace updates on the relation.
+ *
+ * This is used for assertions and for making the executor follow
the
+ * locking protocol described at README.tuplock section "Locking
to write
+ * inplace-updated tables". Extensions may inplace-update other
heap
+ * tables, but concurrent SQL UPDATE on the same table may
overwrite
+ * those modifications.
+ *
+ * The executor can assume these are not partitions or partitioned
and
+ * have no triggers.
*/
bool
IsInplaceUpdateRelation(Relation relation)
diff --git a/src/backend/commands/dbcommands.c
b/src/backend/commands/dbcommands.c
index da4d2b7..fd48022 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -1864,6 +1864,7 @@ RenameDatabase(const char *oldname, const char *newname)
{
Oid db_id;
HeapTuple newtup;
+ ItemPointerData otid;
Relation rel;
int notherbackends;
int npreparedxacts;
@@ -1935,11 +1936,13 @@ RenameDatabase(const char *oldname, const char *newname)
errdetail_busy_db(notherbackends,
npreparedxacts)));
/* rename */
- newtup = SearchSysCacheCopy1(DATABASEOID, ObjectIdGetDatum(db_id));
+ newtup = SearchSysCacheLockedCopy1(DATABASEOID,
ObjectIdGetDatum(db_id));
if (!HeapTupleIsValid(newtup))
elog(ERROR, "cache lookup failed for database %u", db_id);
+ otid = newtup->t_self;
namestrcpy(&(((Form_pg_database) GETSTRUCT(newtup))->datname), newname);
- CatalogTupleUpdate(rel, &newtup->t_self, newtup);
+ CatalogTupleUpdate(rel, &otid, newtup);
+ UnlockTuple(rel, &otid, InplaceUpdateTupleLock);
InvokeObjectPostAlterHook(DatabaseRelationId, db_id, 0);
@@ -2188,6 +2191,7 @@ movedb(const char *dbname, const char *tblspcname)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not
exist", dbname)));
+ LockTuple(pgdbrel, &oldtuple->t_self, InplaceUpdateTupleLock);
new_record[Anum_pg_database_dattablespace - 1] =
ObjectIdGetDatum(dst_tblspcoid);
new_record_repl[Anum_pg_database_dattablespace - 1] = true;
@@ -2196,6 +2200,7 @@ movedb(const char *dbname, const char *tblspcname)
new_record,
new_record_nulls, new_record_repl);
CatalogTupleUpdate(pgdbrel, &oldtuple->t_self, newtuple);
+ UnlockTuple(pgdbrel, &oldtuple->t_self, InplaceUpdateTupleLock);
InvokeObjectPostAlterHook(DatabaseRelationId, db_id, 0);
@@ -2426,6 +2431,7 @@ AlterDatabase(ParseState *pstate, AlterDatabaseStmt
*stmt, bool isTopLevel)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist",
stmt->dbname)));
+ LockTuple(rel, &tuple->t_self, InplaceUpdateTupleLock);
datform = (Form_pg_database) GETSTRUCT(tuple);
dboid = datform->oid;
@@ -2475,6 +2481,7 @@ AlterDatabase(ParseState *pstate, AlterDatabaseStmt
*stmt, bool isTopLevel)
newtuple = heap_modify_tuple(tuple, RelationGetDescr(rel), new_record,
new_record_nulls, new_record_repl);
CatalogTupleUpdate(rel, &tuple->t_self, newtuple);
+ UnlockTuple(rel, &tuple->t_self, InplaceUpdateTupleLock);
InvokeObjectPostAlterHook(DatabaseRelationId, dboid, 0);
@@ -2524,6 +2531,7 @@ AlterDatabaseRefreshColl(AlterDatabaseRefreshCollStmt
*stmt)
if (!object_ownercheck(DatabaseRelationId, db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
stmt->dbname);
+ LockTuple(rel, &tuple->t_self, InplaceUpdateTupleLock);
datum = heap_getattr(tuple, Anum_pg_database_datcollversion,
RelationGetDescr(rel), &isnull);
oldversion = isnull ? NULL : TextDatumGetCString(datum);
@@ -2552,6 +2560,7 @@ AlterDatabaseRefreshColl(AlterDatabaseRefreshCollStmt
*stmt)
bool nulls[Natts_pg_database] = {0};
bool replaces[Natts_pg_database] = {0};
Datum values[Natts_pg_database] = {0};
+ HeapTuple newtuple;
ereport(NOTICE,
(errmsg("changing version from %s to %s",
@@ -2560,14 +2569,15 @@ AlterDatabaseRefreshColl(AlterDatabaseRefreshCollStmt
*stmt)
values[Anum_pg_database_datcollversion - 1] =
CStringGetTextDatum(newversion);
replaces[Anum_pg_database_datcollversion - 1] = true;
- tuple = heap_modify_tuple(tuple, RelationGetDescr(rel),
- values,
nulls, replaces);
- CatalogTupleUpdate(rel, &tuple->t_self, tuple);
- heap_freetuple(tuple);
+ newtuple = heap_modify_tuple(tuple, RelationGetDescr(rel),
+
values, nulls, replaces);
+ CatalogTupleUpdate(rel, &tuple->t_self, newtuple);
+ heap_freetuple(newtuple);
}
else
ereport(NOTICE,
(errmsg("version has not changed")));
+ UnlockTuple(rel, &tuple->t_self, InplaceUpdateTupleLock);
InvokeObjectPostAlterHook(DatabaseRelationId, db_id, 0);
@@ -2679,6 +2689,8 @@ AlterDatabaseOwner(const char *dbname, Oid newOwnerId)
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to change
owner of database")));
+ LockTuple(rel, &tuple->t_self, InplaceUpdateTupleLock);
+
repl_repl[Anum_pg_database_datdba - 1] = true;
repl_val[Anum_pg_database_datdba - 1] =
ObjectIdGetDatum(newOwnerId);
@@ -2700,6 +2712,7 @@ AlterDatabaseOwner(const char *dbname, Oid newOwnerId)
newtuple = heap_modify_tuple(tuple, RelationGetDescr(rel),
repl_val, repl_null, repl_repl);
CatalogTupleUpdate(rel, &newtuple->t_self, newtuple);
+ UnlockTuple(rel, &tuple->t_self, InplaceUpdateTupleLock);
heap_freetuple(newtuple);
diff --git a/src/backend/commands/event_trigger.c
b/src/backend/commands/event_trigger.c
index 22d0ce7..36d82bd 100644
--- a/src/backend/commands/event_trigger.c
+++ b/src/backend/commands/event_trigger.c
@@ -388,6 +388,7 @@ SetDatabaseHasLoginEventTriggers(void)
/* Set dathasloginevt flag in pg_database */
Form_pg_database db;
Relation pg_db = table_open(DatabaseRelationId,
RowExclusiveLock);
+ ItemPointerData otid;
HeapTuple tuple;
/*
@@ -399,16 +400,18 @@ SetDatabaseHasLoginEventTriggers(void)
*/
LockSharedObject(DatabaseRelationId, MyDatabaseId, 0,
AccessExclusiveLock);
- tuple = SearchSysCacheCopy1(DATABASEOID,
ObjectIdGetDatum(MyDatabaseId));
+ tuple = SearchSysCacheLockedCopy1(DATABASEOID,
ObjectIdGetDatum(MyDatabaseId));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for database %u",
MyDatabaseId);
+ otid = tuple->t_self;
db = (Form_pg_database) GETSTRUCT(tuple);
if (!db->dathasloginevt)
{
db->dathasloginevt = true;
- CatalogTupleUpdate(pg_db, &tuple->t_self, tuple);
+ CatalogTupleUpdate(pg_db, &otid, tuple);
CommandCounterIncrement();
}
+ UnlockTuple(pg_db, &otid, InplaceUpdateTupleLock);
table_close(pg_db, RowExclusiveLock);
heap_freetuple(tuple);
}
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 2caab88..8d04ca0 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -4409,14 +4409,17 @@ update_relispartition(Oid relationId, bool newval)
{
HeapTuple tup;
Relation classRel;
+ ItemPointerData otid;
classRel = table_open(RelationRelationId, RowExclusiveLock);
- tup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relationId));
+ tup = SearchSysCacheLockedCopy1(RELOID, ObjectIdGetDatum(relationId));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for relation %u", relationId);
+ otid = tup->t_self;
Assert(((Form_pg_class) GETSTRUCT(tup))->relispartition != newval);
((Form_pg_class) GETSTRUCT(tup))->relispartition = newval;
- CatalogTupleUpdate(classRel, &tup->t_self, tup);
+ CatalogTupleUpdate(classRel, &otid, tup);
+ UnlockTuple(classRel, &otid, InplaceUpdateTupleLock);
heap_freetuple(tup);
table_close(classRel, RowExclusiveLock);
}
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8fcb188..7fa80a5 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3609,6 +3609,7 @@ SetRelationTableSpace(Relation rel,
{
Relation pg_class;
HeapTuple tuple;
+ ItemPointerData otid;
Form_pg_class rd_rel;
Oid reloid = RelationGetRelid(rel);
@@ -3617,9 +3618,10 @@ SetRelationTableSpace(Relation rel,
/* Get a modifiable copy of the relation's pg_class row. */
pg_class = table_open(RelationRelationId, RowExclusiveLock);
- tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(reloid));
+ tuple = SearchSysCacheLockedCopy1(RELOID, ObjectIdGetDatum(reloid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", reloid);
+ otid = tuple->t_self;
rd_rel = (Form_pg_class) GETSTRUCT(tuple);
/* Update the pg_class row. */
@@ -3627,7 +3629,8 @@ SetRelationTableSpace(Relation rel,
InvalidOid : newTableSpaceId;
if (RelFileNumberIsValid(newRelFilenumber))
rd_rel->relfilenode = newRelFilenumber;
- CatalogTupleUpdate(pg_class, &tuple->t_self, tuple);
+ CatalogTupleUpdate(pg_class, &otid, tuple);
+ UnlockTuple(pg_class, &otid, InplaceUpdateTupleLock);
/*
* Record dependency on tablespace. This is only required for relations
@@ -4121,6 +4124,7 @@ RenameRelationInternal(Oid myrelid, const char
*newrelname, bool is_internal, bo
{
Relation targetrelation;
Relation relrelation; /* for RELATION relation */
+ ItemPointerData otid;
HeapTuple reltup;
Form_pg_class relform;
Oid namespaceId;
@@ -4143,7 +4147,8 @@ RenameRelationInternal(Oid myrelid, const char
*newrelname, bool is_internal, bo
*/
relrelation = table_open(RelationRelationId, RowExclusiveLock);
- reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(myrelid));
+ reltup = SearchSysCacheLockedCopy1(RELOID, ObjectIdGetDatum(myrelid));
+ otid = reltup->t_self;
if (!HeapTupleIsValid(reltup)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for relation %u", myrelid);
relform = (Form_pg_class) GETSTRUCT(reltup);
@@ -4170,7 +4175,8 @@ RenameRelationInternal(Oid myrelid, const char
*newrelname, bool is_internal, bo
*/
namestrcpy(&(relform->relname), newrelname);
- CatalogTupleUpdate(relrelation, &reltup->t_self, reltup);
+ CatalogTupleUpdate(relrelation, &otid, reltup);
+ UnlockTuple(relrelation, &otid, InplaceUpdateTupleLock);
InvokeObjectPostAlterHookArg(RelationRelationId, myrelid, 0,
InvalidOid,
is_internal);
@@ -14917,7 +14923,7 @@ ATExecSetRelOptions(Relation rel, List *defList,
AlterTableType operation,
/* Fetch heap tuple */
relid = RelationGetRelid(rel);
- tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
+ tuple = SearchSysCacheLocked1(RELOID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relid);
@@ -15021,6 +15027,7 @@ ATExecSetRelOptions(Relation rel, List *defList,
AlterTableType operation,
repl_val,
repl_null, repl_repl);
CatalogTupleUpdate(pgclass, &newtuple->t_self, newtuple);
+ UnlockTuple(pgclass, &tuple->t_self, InplaceUpdateTupleLock);
InvokeObjectPostAlterHook(RelationRelationId, RelationGetRelid(rel), 0);
@@ -17170,7 +17177,8 @@ AlterRelationNamespaceInternal(Relation classRel, Oid
relOid,
ObjectAddress thisobj;
bool already_done = false;
- classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relOid));
+ /* no rel lock for relkind=c so use LOCKTAG_TUPLE */
+ classTup = SearchSysCacheLockedCopy1(RELOID, ObjectIdGetDatum(relOid));
if (!HeapTupleIsValid(classTup))
elog(ERROR, "cache lookup failed for relation %u", relOid);
classForm = (Form_pg_class) GETSTRUCT(classTup);
@@ -17189,6 +17197,8 @@ AlterRelationNamespaceInternal(Relation classRel, Oid
relOid,
already_done = object_address_present(&thisobj, objsMoved);
if (!already_done && oldNspOid != newNspOid)
{
+ ItemPointerData otid = classTup->t_self;
+
/* check for duplicate name (more friendly than unique-index
failure) */
if (get_relname_relid(NameStr(classForm->relname),
newNspOid) !=
InvalidOid)
@@ -17201,7 +17211,9 @@ AlterRelationNamespaceInternal(Relation classRel, Oid
relOid,
/* classTup is a copy, so OK to scribble on */
classForm->relnamespace = newNspOid;
- CatalogTupleUpdate(classRel, &classTup->t_self, classTup);
+ CatalogTupleUpdate(classRel, &otid, classTup);
+ UnlockTuple(classRel, &otid, InplaceUpdateTupleLock);
+
/* Update dependency on schema if caller said so */
if (hasDependEntry &&
@@ -17213,6 +17225,8 @@ AlterRelationNamespaceInternal(Relation classRel, Oid
relOid,
elog(ERROR, "could not change schema dependency for
relation \"%s\"",
NameStr(classForm->relname));
}
+ else
+ UnlockTuple(classRel, &classTup->t_self,
InplaceUpdateTupleLock);
if (!already_done)
{
add_exact_object_address(&thisobj, objsMoved);
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 4d7c92d..321ad47 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1209,6 +1209,8 @@ InitResultRelInfo(ResultRelInfo *resultRelInfo,
resultRelInfo->ri_NumIndices = 0;
resultRelInfo->ri_IndexRelationDescs = NULL;
resultRelInfo->ri_IndexRelationInfo = NULL;
+ resultRelInfo->ri_needLockTagTuple =
+ IsInplaceUpdateRelation(resultRelationDesc);
/* make a copy so as not to depend on relcache info not changing... */
resultRelInfo->ri_TrigDesc =
CopyTriggerDesc(resultRelationDesc->trigdesc);
if (resultRelInfo->ri_TrigDesc)
diff --git a/src/backend/executor/execReplication.c
b/src/backend/executor/execReplication.c
index d0a89cd..f18efdb 100644
--- a/src/backend/executor/execReplication.c
+++ b/src/backend/executor/execReplication.c
@@ -559,8 +559,12 @@ ExecSimpleRelationUpdate(ResultRelInfo *resultRelInfo,
Relation rel = resultRelInfo->ri_RelationDesc;
ItemPointer tid = &(searchslot->tts_tid);
- /* For now we support only tables. */
+ /*
+ * We support only non-system tables, with
+ * check_publication_add_relation() accountable.
+ */
Assert(rel->rd_rel->relkind == RELKIND_RELATION);
+ Assert(!IsCatalogRelation(rel));
CheckCmdReplicaIdentity(rel, CMD_UPDATE);
diff --git a/src/backend/executor/nodeModifyTable.c
b/src/backend/executor/nodeModifyTable.c
index 4913e49..02be418 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2321,6 +2321,8 @@ ExecUpdate(ModifyTableContext *context, ResultRelInfo
*resultRelInfo,
}
else
{
+ ItemPointerData lockedtid;
+
/*
* If we generate a new candidate tuple after EvalPlanQual
testing, we
* must loop back here to try again. (We don't need to redo
triggers,
@@ -2329,6 +2331,7 @@ ExecUpdate(ModifyTableContext *context, ResultRelInfo
*resultRelInfo,
* to do them again.)
*/
redo_act:
+ lockedtid = *tupleid;
result = ExecUpdateAct(context, resultRelInfo, tupleid,
oldtuple, slot,
canSetTag,
&updateCxt);
@@ -2422,6 +2425,14 @@ redo_act:
ExecInitUpdateProjection(context->mtstate,
resultRelInfo);
+ if
(resultRelInfo->ri_needLockTagTuple)
+ {
+
UnlockTuple(resultRelationDesc,
+
&lockedtid, InplaceUpdateTupleLock);
+
LockTuple(resultRelationDesc,
+
tupleid, InplaceUpdateTupleLock);
+ }
+
/* Fetch the most
recent version of old tuple. */
oldSlot =
resultRelInfo->ri_oldTupleSlot;
if
(!table_tuple_fetch_row_version(resultRelationDesc,
@@ -2526,6 +2537,14 @@ ExecOnConflictUpdate(ModifyTableContext *context,
TransactionId xmin;
bool isnull;
+ /*
+ * Parse analysis should have blocked ON CONFLICT for all system
+ * relations, which includes these. There's no fundamental obstacle to
+ * supporting this; we'd just need to handle LOCKTAG_TUPLE like the
other
+ * ExecUpdate() caller.
+ */
+ Assert(!resultRelInfo->ri_needLockTagTuple);
+
/* Determine lock mode to use */
lockmode = ExecUpdateLockMode(context->estate, resultRelInfo);
@@ -2851,6 +2870,7 @@ ExecMergeMatched(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
{
ModifyTableState *mtstate = context->mtstate;
List **mergeActions = resultRelInfo->ri_MergeActions;
+ ItemPointerData lockedtid;
List *actionStates;
TupleTableSlot *newslot = NULL;
TupleTableSlot *rslot = NULL;
@@ -2887,14 +2907,32 @@ ExecMergeMatched(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
* target wholerow junk attr.
*/
Assert(tupleid != NULL || oldtuple != NULL);
+ ItemPointerSetInvalid(&lockedtid);
if (oldtuple != NULL)
+ {
+ Assert(!resultRelInfo->ri_needLockTagTuple);
ExecForceStoreHeapTuple(oldtuple,
resultRelInfo->ri_oldTupleSlot,
false);
- else if (!table_tuple_fetch_row_version(resultRelInfo->ri_RelationDesc,
-
tupleid,
-
SnapshotAny,
-
resultRelInfo->ri_oldTupleSlot))
- elog(ERROR, "failed to fetch the target tuple");
+ }
+ else
+ {
+ if (resultRelInfo->ri_needLockTagTuple)
+ {
+ /*
+ * This locks even for CMD_DELETE, for CMD_NOTHING, and
for tuples
+ * that don't match mas_whenqual. MERGE on system
catalogs is a
+ * minor use case, so don't bother optimizing those.
+ */
+ LockTuple(resultRelInfo->ri_RelationDesc, tupleid,
+ InplaceUpdateTupleLock);
+ lockedtid = *tupleid;
+ }
+ if
(!table_tuple_fetch_row_version(resultRelInfo->ri_RelationDesc,
+
tupleid,
+
SnapshotAny,
+
resultRelInfo->ri_oldTupleSlot))
+ elog(ERROR, "failed to fetch the target tuple");
+ }
/*
* Test the join condition. If it's satisfied, perform a MATCHED
action.
@@ -2966,7 +3004,7 @@ lmerge_matched:
tupleid, NULL, newslot, &result))
{
if (result == TM_Ok)
- return NULL; /* "do nothing"
*/
+ goto out; /* "do nothing"
*/
break; /* concurrent
update/delete */
}
@@ -2977,11 +3015,11 @@ lmerge_matched:
{
if (!ExecIRUpdateTriggers(estate,
resultRelInfo,
oldtuple, newslot))
- return NULL; /* "do nothing"
*/
+ goto out; /* "do nothing"
*/
}
else
{
- /* called
table_tuple_fetch_row_version() above */
+ /* checked ri_needLockTagTuple above */
Assert(oldtuple == NULL);
result = ExecUpdateAct(context,
resultRelInfo, tupleid,
@@ -3000,7 +3038,8 @@ lmerge_matched:
if (updateCxt.crossPartUpdate)
{
mtstate->mt_merge_updated += 1;
- return
context->cpUpdateReturningSlot;
+ rslot =
context->cpUpdateReturningSlot;
+ goto out;
}
}
@@ -3018,7 +3057,7 @@ lmerge_matched:
NULL, NULL, &result))
{
if (result == TM_Ok)
- return NULL; /* "do nothing"
*/
+ goto out; /* "do nothing"
*/
break; /* concurrent
update/delete */
}
@@ -3029,11 +3068,11 @@ lmerge_matched:
{
if (!ExecIRDeleteTriggers(estate,
resultRelInfo,
oldtuple))
- return NULL; /* "do nothing"
*/
+ goto out; /* "do nothing"
*/
}
else
{
- /* called
table_tuple_fetch_row_version() above */
+ /* checked ri_needLockTagTuple above */
Assert(oldtuple == NULL);
result = ExecDeleteAct(context,
resultRelInfo, tupleid,
@@ -3115,7 +3154,7 @@ lmerge_matched:
* let caller handle it under NOT MATCHED [BY
TARGET] clauses.
*/
*matched = false;
- return NULL;
+ goto out;
case TM_Updated:
{
@@ -3189,7 +3228,7 @@ lmerge_matched:
* more to do.
*/
if
(TupIsNull(epqslot))
- return
NULL;
+ goto
out;
/*
* If we got a
NULL ctid from the subplan, the
@@ -3207,6 +3246,15 @@ lmerge_matched:
* we need to
switch to the NOT MATCHED BY
* SOURCE case.
*/
+ if
(resultRelInfo->ri_needLockTagTuple)
+ {
+ if
(ItemPointerIsValid(&lockedtid))
+
UnlockTuple(resultRelInfo->ri_RelationDesc, &lockedtid,
+
InplaceUpdateTupleLock);
+
LockTuple(resultRelInfo->ri_RelationDesc, &context->tmfd.ctid,
+
InplaceUpdateTupleLock);
+
lockedtid = context->tmfd.ctid;
+ }
if
(!table_tuple_fetch_row_version(resultRelationDesc,
&context->tmfd.ctid,
SnapshotAny,
@@ -3235,7 +3283,7 @@ lmerge_matched:
* MATCHED [BY TARGET]
actions
*/
*matched = false;
- return NULL;
+ goto out;
case TM_SelfModified:
@@ -3263,13 +3311,13 @@ lmerge_matched:
/* This shouldn't
happen */
elog(ERROR, "attempted
to update or delete invisible tuple");
- return NULL;
+ goto out;
default:
/* see table_tuple_lock
call in ExecDelete() */
elog(ERROR, "unexpected
table_tuple_lock status: %u",
result);
- return NULL;
+ goto out;
}
}
@@ -3316,6 +3364,10 @@ lmerge_matched:
/*
* Successfully executed an action or no qualifying action was found.
*/
+out:
+ if (ItemPointerIsValid(&lockedtid))
+ UnlockTuple(resultRelInfo->ri_RelationDesc, &lockedtid,
+ InplaceUpdateTupleLock);
return rslot;
}
@@ -3767,6 +3819,7 @@ ExecModifyTable(PlanState *pstate)
HeapTupleData oldtupdata;
HeapTuple oldtuple;
ItemPointer tupleid;
+ bool tuplock;
CHECK_FOR_INTERRUPTS();
@@ -4079,6 +4132,8 @@ ExecModifyTable(PlanState *pstate)
break;
case CMD_UPDATE:
+ tuplock = false;
+
/* Initialize projection info if first time for
this table */
if
(unlikely(!resultRelInfo->ri_projectNewInfoValid))
ExecInitUpdateProjection(node,
resultRelInfo);
@@ -4090,6 +4145,7 @@ ExecModifyTable(PlanState *pstate)
oldSlot = resultRelInfo->ri_oldTupleSlot;
if (oldtuple != NULL)
{
+
Assert(!resultRelInfo->ri_needLockTagTuple);
/* Use the wholerow junk attr as the
old tuple. */
ExecForceStoreHeapTuple(oldtuple,
oldSlot, false);
}
@@ -4098,6 +4154,11 @@ ExecModifyTable(PlanState *pstate)
/* Fetch the most recent version of old
tuple. */
Relation relation =
resultRelInfo->ri_RelationDesc;
+ if (resultRelInfo->ri_needLockTagTuple)
+ {
+ LockTuple(relation, tupleid,
InplaceUpdateTupleLock);
+ tuplock = true;
+ }
if
(!table_tuple_fetch_row_version(relation, tupleid,
SnapshotAny,
oldSlot))
@@ -4109,6 +4170,9 @@ ExecModifyTable(PlanState *pstate)
/* Now apply the update. */
slot = ExecUpdate(&context, resultRelInfo,
tupleid, oldtuple,
slot,
node->canSetTag);
+ if (tuplock)
+
UnlockTuple(resultRelInfo->ri_RelationDesc, tupleid,
+
InplaceUpdateTupleLock);
break;
case CMD_DELETE:
diff --git a/src/backend/utils/cache/relcache.c
b/src/backend/utils/cache/relcache.c
index 930cc03..3f1e8ce 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -3770,6 +3770,7 @@ RelationSetNewRelfilenumber(Relation relation, char
persistence)
{
RelFileNumber newrelfilenumber;
Relation pg_class;
+ ItemPointerData otid;
HeapTuple tuple;
Form_pg_class classform;
MultiXactId minmulti = InvalidMultiXactId;
@@ -3812,11 +3813,12 @@ RelationSetNewRelfilenumber(Relation relation, char
persistence)
*/
pg_class = table_open(RelationRelationId, RowExclusiveLock);
- tuple = SearchSysCacheCopy1(RELOID,
-
ObjectIdGetDatum(RelationGetRelid(relation)));
+ tuple = SearchSysCacheLockedCopy1(RELOID,
+
ObjectIdGetDatum(RelationGetRelid(relation)));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for relation %u",
RelationGetRelid(relation));
+ otid = tuple->t_self;
classform = (Form_pg_class) GETSTRUCT(tuple);
/*
@@ -3936,9 +3938,10 @@ RelationSetNewRelfilenumber(Relation relation, char
persistence)
classform->relminmxid = minmulti;
classform->relpersistence = persistence;
- CatalogTupleUpdate(pg_class, &tuple->t_self, tuple);
+ CatalogTupleUpdate(pg_class, &otid, tuple);
}
+ UnlockTuple(pg_class, &otid, InplaceUpdateTupleLock);
heap_freetuple(tuple);
table_close(pg_class, RowExclusiveLock);
diff --git a/src/backend/utils/cache/syscache.c
b/src/backend/utils/cache/syscache.c
index 3e03dfc..50c9440 100644
--- a/src/backend/utils/cache/syscache.c
+++ b/src/backend/utils/cache/syscache.c
@@ -30,7 +30,10 @@
#include "catalog/pg_shseclabel_d.h"
#include "common/int.h"
#include "lib/qunique.h"
+#include "miscadmin.h"
+#include "storage/lmgr.h"
#include "utils/catcache.h"
+#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
@@ -269,6 +272,98 @@ ReleaseSysCache(HeapTuple tuple)
}
/*
+ * SearchSysCacheLocked1
+ *
+ * Combine SearchSysCache1() with acquiring a LOCKTAG_TUPLE at mode
+ * InplaceUpdateTupleLock. This is a tool for complying with the
+ * README.tuplock section "Locking to write inplace-updated tables". After
+ * the caller's heap_update(), it should UnlockTuple(InplaceUpdateTupleLock)
+ * and ReleaseSysCache().
+ *
+ * The returned tuple may be the subject of an uncommitted update, so this
+ * doesn't prevent the "tuple concurrently updated" error.
+ */
+HeapTuple
+SearchSysCacheLocked1(int cacheId,
+ Datum key1)
+{
+ ItemPointerData tid;
+ LOCKTAG tag;
+ Oid dboid =
+ SysCache[cacheId]->cc_relisshared ? InvalidOid : MyDatabaseId;
+ Oid reloid = cacheinfo[cacheId].reloid;
+
+ /*----------
+ * Since inplace updates may happen just before our LockTuple(), we must
+ * return content acquired after LockTuple() of the TID we return. If
we
+ * just fetched twice instead of looping, the following sequence would
+ * defeat our locking:
+ *
+ * GRANT: SearchSysCache1() = TID (1,5)
+ * GRANT: LockTuple(pg_class, (1,5))
+ * [no more inplace update of (1,5) until we release the lock]
+ * CLUSTER: SearchSysCache1() = TID (1,5)
+ * CLUSTER: heap_update() = TID (1,8)
+ * CLUSTER: COMMIT
+ * GRANT: SearchSysCache1() = TID (1,8)
+ * GRANT: return (1,8) from SearchSysCacheLocked1()
+ * VACUUM: SearchSysCache1() = TID (1,8)
+ * VACUUM: LockTuple(pg_class, (1,8)) # two TIDs now locked for one
rel
+ * VACUUM: inplace update
+ * GRANT: heap_update() = (1,9) # lose inplace update
+ *
+ * In the happy case, this takes two fetches, one to determine the TID
to
+ * lock and another to get the content and confirm the TID didn't
change.
+ *
+ * This is valid even if the row gets updated to a new TID, the old TID
+ * becomes LP_UNUSED, and the row gets updated back to its old TID.
We'd
+ * still hold the right LOCKTAG_TUPLE and a copy of the row captured
after
+ * the LOCKTAG_TUPLE.
+ */
+ ItemPointerSetInvalid(&tid);
+ for (;;)
+ {
+ HeapTuple tuple;
+ LOCKMODE lockmode = InplaceUpdateTupleLock;
+
+ tuple = SearchSysCache1(cacheId, key1);
+ if (ItemPointerIsValid(&tid))
+ {
+ if (!HeapTupleIsValid(tuple))
+ {
+ LockRelease(&tag, lockmode, false);
+ return tuple;
+ }
+ if (ItemPointerEquals(&tid, &tuple->t_self))
+ return tuple;
+ LockRelease(&tag, lockmode, false);
+ }
+ else if (!HeapTupleIsValid(tuple))
+ return tuple;
+
+ tid = tuple->t_self;
+ ReleaseSysCache(tuple);
+ /* like: LockTuple(rel, &tid, lockmode) */
+ SET_LOCKTAG_TUPLE(tag, dboid, reloid,
+
ItemPointerGetBlockNumber(&tid),
+
ItemPointerGetOffsetNumber(&tid));
+ (void) LockAcquire(&tag, lockmode, false, false);
+
+ /*
+ * If an inplace update just finished, ensure we process the
syscache
+ * inval. XXX this is insufficient: the inplace updater may
not yet
+ * have reached AtEOXact_Inval(). See test at
inplace-inval.spec.
+ *
+ * If a heap_update() call just released its LOCKTAG_TUPLE,
we'll
+ * probably find the old tuple and reach "tuple concurrently
updated".
+ * If that heap_update() aborts, our LOCKTAG_TUPLE blocks
inplace
+ * updates while our caller works.
+ */
+ AcceptInvalidationMessages();
+ }
+}
+
+/*
* SearchSysCacheCopy
*
* A convenience routine that does SearchSysCache and (if successful)
@@ -295,6 +390,28 @@ SearchSysCacheCopy(int cacheId,
}
/*
+ * SearchSysCacheLockedCopy1
+ *
+ * Meld SearchSysCacheLockedCopy1 with SearchSysCacheCopy(). After the
+ * caller's heap_update(), it should UnlockTuple(InplaceUpdateTupleLock) and
+ * heap_freetuple().
+ */
+HeapTuple
+SearchSysCacheLockedCopy1(int cacheId,
+ Datum key1)
+{
+ HeapTuple tuple,
+ newtuple;
+
+ tuple = SearchSysCacheLocked1(cacheId, key1);
+ if (!HeapTupleIsValid(tuple))
+ return tuple;
+ newtuple = heap_copytuple(tuple);
+ ReleaseSysCache(tuple);
+ return newtuple;
+}
+
+/*
* SearchSysCacheExists
*
* A convenience routine that just probes to see if a tuple can be found.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index b62c96f..eab0add 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -482,6 +482,9 @@ typedef struct ResultRelInfo
/* Have the projection and the slots above been initialized? */
bool ri_projectNewInfoValid;
+ /* updates do LockTuple() before oldtup read; see README.tuplock */
+ bool ri_needLockTagTuple;
+
/* triggers to be fired, if any */
TriggerDesc *ri_TrigDesc;
diff --git a/src/include/storage/lockdefs.h b/src/include/storage/lockdefs.h
index 934ba84..810b297 100644
--- a/src/include/storage/lockdefs.h
+++ b/src/include/storage/lockdefs.h
@@ -47,6 +47,8 @@ typedef int LOCKMODE;
#define MaxLockMode 8 /* highest standard
lock mode */
+/* See README.tuplock section "Locking to write inplace-updated tables" */
+#define InplaceUpdateTupleLock ExclusiveLock
/* WAL representation of an AccessExclusiveLock on a table */
typedef struct xl_standby_lock
diff --git a/src/include/utils/syscache.h b/src/include/utils/syscache.h
index 03a27dd..b541911 100644
--- a/src/include/utils/syscache.h
+++ b/src/include/utils/syscache.h
@@ -43,9 +43,14 @@ extern HeapTuple SearchSysCache4(int cacheId,
extern void ReleaseSysCache(HeapTuple tuple);
+extern HeapTuple SearchSysCacheLocked1(int cacheId,
+
Datum key1);
+
/* convenience routines */
extern HeapTuple SearchSysCacheCopy(int cacheId,
Datum
key1, Datum key2, Datum key3, Datum key4);
+extern HeapTuple SearchSysCacheLockedCopy1(int cacheId,
+
Datum key1);
extern bool SearchSysCacheExists(int cacheId,
Datum key1,
Datum key2, Datum key3, Datum key4);
extern Oid GetSysCacheOid(int cacheId, AttrNumber oidcol,
diff --git a/src/test/isolation/expected/intra-grant-inplace.out
b/src/test/isolation/expected/intra-grant-inplace.out
index c2a9841..b5fe8b0 100644
--- a/src/test/isolation/expected/intra-grant-inplace.out
+++ b/src/test/isolation/expected/intra-grant-inplace.out
@@ -154,9 +154,11 @@ step b1: BEGIN;
step grant1:
GRANT SELECT ON intra_grant_inplace TO PUBLIC;
<waiting ...>
-step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c);
-step c2: COMMIT;
+step addk2: ALTER TABLE intra_grant_inplace ADD PRIMARY KEY (c); <waiting ...>
+step addk2: <... completed>
+ERROR: deadlock detected
step grant1: <... completed>
+step c2: COMMIT;
step c1: COMMIT;
step read2:
SELECT relhasindex FROM pg_class
@@ -194,9 +196,8 @@ relhasindex
f
(1 row)
-s4: WARNING: got: tuple concurrently updated
-step revoke4: <... completed>
step r3: ROLLBACK;
+step revoke4: <... completed>
starting permutation: b1 drop1 b3 sfu3 revoke4 c1 r3
step b1: BEGIN;
@@ -223,6 +224,6 @@ relhasindex
-----------
(0 rows)
-s4: WARNING: got: tuple concurrently deleted
+s4: WARNING: got: cache lookup failed for relation REDACTED
step revoke4: <... completed>
step r3: ROLLBACK;
diff --git a/src/test/isolation/specs/eval-plan-qual.spec
b/src/test/isolation/specs/eval-plan-qual.spec
index 3a74406..07307e6 100644
--- a/src/test/isolation/specs/eval-plan-qual.spec
+++ b/src/test/isolation/specs/eval-plan-qual.spec
@@ -194,7 +194,7 @@ step simplepartupdate_noroute {
update parttbl set b = 2 where c = 1 returning *;
}
-# test system class updates
+# test system class LockTuple()
step sys1 {
UPDATE pg_class SET reltuples = 123 WHERE oid = 'accounts'::regclass;
diff --git a/src/test/isolation/specs/intra-grant-inplace.spec
b/src/test/isolation/specs/intra-grant-inplace.spec
index eed0b52..2992c85 100644
--- a/src/test/isolation/specs/intra-grant-inplace.spec
+++ b/src/test/isolation/specs/intra-grant-inplace.spec
@@ -14,6 +14,7 @@ teardown
# heap_update()
session s1
+setup { SET deadlock_timeout = '100s'; }
step b1 { BEGIN; }
step grant1 {
GRANT SELECT ON intra_grant_inplace TO PUBLIC;
@@ -25,6 +26,7 @@ step c1 { COMMIT; }
# inplace update
session s2
+setup { SET deadlock_timeout = '10ms'; }
step read2 {
SELECT relhasindex FROM pg_class
WHERE oid = 'intra_grant_inplace'::regclass;
@@ -73,8 +75,6 @@ step keyshr5 {
teardown { ROLLBACK; }
-# XXX extant bugs: permutation comments refer to planned future LockTuple()
-
permutation
b1
grant1
@@ -126,8 +126,8 @@ permutation
b2
sfnku2
b1
- grant1(c2) # acquire LockTuple(), await sfnku2 xmax
- addk2 # block in LockTuple() behind grant1 = deadlock
+ grant1(addk2) # acquire LockTuple(), await sfnku2 xmax
+ addk2(*) # block in LockTuple() behind grant1 = deadlock
c2
c1
read2
@@ -138,7 +138,7 @@ permutation
grant1
b3
sfu3(c1) # acquire LockTuple(), await grant1 xmax
- revoke4(sfu3) # block in LockTuple() behind sfu3
+ revoke4(r3) # block in LockTuple() behind sfu3
c1
r3 # revoke4 unlocks old tuple and finds new
