On 2025/03/11 16:50, Yuki Seino wrote:
Instead, wouldn't it be simpler to update LockAcquireExtended() to
take a new argument, like logLockFailure, to control whether
a lock failure should be logged directly? I’ve adjusted the patch
accordingly and attached it. Please let me know what you think!
Regards,
Thank you!
It's very simple and nice.
It seems like it can also handle other lock failure cases by extending
logLockFailure.
> I agree with this propose.
Thanks for reviewing the patch!
I've made some minor cosmetic adjustments. The updated patch is attached.
Unless there are any objections, I'll proceed with committing it.
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
From b6ad757e99456d379c1a1ec90cac73cd034d8926 Mon Sep 17 00:00:00 2001
From: Fujii Masao <fu...@postgresql.org>
Date: Tue, 11 Mar 2025 19:59:09 +0900
Subject: [PATCH v10] Add GUC option to log lock acquisition failures.
This commit introduces a new GUC, log_lock_failure, which controls whether
a detailed log message is produced when a lock acquisition fails. Currently,
it only supports logging lock failures caused by SELECT ... NOWAIT.
The log message includes information about all processes holding or
waiting for the lock that couldn't be acquired, helping users analyze and
diagnose the causes of lock failures.
This mechanism can be extended in the future to support for logging
lock failures from other commands, such as LOCK TABLE ... NOWAIT.
Author: Yuki Seino <sein...@oss.nttdata.com>
Co-authored-by: Fujii Masao <masao.fu...@gmail.com>
Reviewed-by: Jelte Fennema-Nio <postg...@jeltef.nl>
Discussion: https://postgr.es/m/411280a186cc26ef7034e0f2dfe54...@oss.nttdata.com
---
doc/src/sgml/config.sgml | 20 +++
src/backend/access/heap/heapam.c | 33 +++--
src/backend/access/heap/heapam_handler.c | 4 +-
src/backend/storage/lmgr/lmgr.c | 33 +++--
src/backend/storage/lmgr/lock.c | 55 +++++++-
src/backend/storage/lmgr/proc.c | 129 +++++++++++-------
src/backend/utils/misc/guc_tables.c | 9 ++
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/include/storage/lmgr.h | 5 +-
src/include/storage/lock.h | 4 +-
src/include/storage/proc.h | 4 +
11 files changed, 211 insertions(+), 86 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d2fa5f7d1a9..3e85bf76dd5 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -7678,6 +7678,26 @@ log_line_prefix = '%m [%p] %q%u@%d/%a '
</listitem>
</varlistentry>
+ <varlistentry id="guc-log-lock-failure" xreflabel="log_lock_failure">
+ <term><varname>log_lock_failure</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>log_lock_failure</varname> configuration
parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Controls whether a detailed log message is produced
+ when a lock acquisition fails. This is useful for analyzing
+ the causes of lock failures. Currently, only lock failures
+ due to <literal>SELECT NOWAIT</literal> is supported.
+ The default is <literal>off</literal>. Only superusers and
+ users with the appropriate <literal>SET</literal> privilege
+ can change this setting.
+ </para>
+ </listitem>
+ </varlistentry>
+
+
<varlistentry id="guc-log-recovery-conflict-waits"
xreflabel="log_recovery_conflict_waits">
<term><varname>log_recovery_conflict_waits</varname>
(<type>boolean</type>)
<indexterm>
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index fa7935a0ed3..21575a8ffef 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -98,7 +98,8 @@ static void MultiXactIdWait(MultiXactId multi,
MultiXactStatus status, uint16 in
Relation rel,
ItemPointer ctid, XLTW_Oper oper,
int *remaining);
static bool ConditionalMultiXactIdWait(MultiXactId multi, MultiXactStatus
status,
-
uint16 infomask, Relation rel, int *remaining);
+
uint16 infomask, Relation rel, int *remaining,
+ bool
logLockFailure);
static void index_delete_sort(TM_IndexDeleteOp *delstate);
static int bottomup_sort_and_shrink(TM_IndexDeleteOp *delstate);
static XLogRecPtr log_heap_new_cid(Relation relation, HeapTuple tup);
@@ -162,8 +163,8 @@ static const struct
LockTuple((rel), (tup), tupleLockExtraInfo[mode].hwlock)
#define UnlockTupleTuplock(rel, tup, mode) \
UnlockTuple((rel), (tup), tupleLockExtraInfo[mode].hwlock)
-#define ConditionalLockTupleTuplock(rel, tup, mode) \
- ConditionalLockTuple((rel), (tup), tupleLockExtraInfo[mode].hwlock)
+#define ConditionalLockTupleTuplock(rel, tup, mode, log) \
+ ConditionalLockTuple((rel), (tup), tupleLockExtraInfo[mode].hwlock,
(log))
#ifdef USE_PREFETCH
/*
@@ -4894,7 +4895,7 @@ l3:
case LockWaitSkip:
if
(!ConditionalMultiXactIdWait((MultiXactId) xwait,
status, infomask, relation,
-
NULL))
+
NULL, false))
{
result = TM_WouldBlock;
/* recovery code
expects to have buffer lock held */
@@ -4905,7 +4906,7 @@ l3:
case LockWaitError:
if
(!ConditionalMultiXactIdWait((MultiXactId) xwait,
status, infomask, relation,
-
NULL))
+
NULL, log_lock_failure))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
@@ -4934,7 +4935,7 @@ l3:
XLTW_Lock);
break;
case LockWaitSkip:
- if
(!ConditionalXactLockTableWait(xwait))
+ if
(!ConditionalXactLockTableWait(xwait, false))
{
result = TM_WouldBlock;
/* recovery code
expects to have buffer lock held */
@@ -4943,7 +4944,7 @@ l3:
}
break;
case LockWaitError:
- if
(!ConditionalXactLockTableWait(xwait))
+ if
(!ConditionalXactLockTableWait(xwait, log_lock_failure))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
@@ -5203,12 +5204,12 @@ heap_acquire_tuplock(Relation relation, ItemPointer
tid, LockTupleMode mode,
break;
case LockWaitSkip:
- if (!ConditionalLockTupleTuplock(relation, tid, mode))
+ if (!ConditionalLockTupleTuplock(relation, tid, mode,
false))
return false;
break;
case LockWaitError:
- if (!ConditionalLockTupleTuplock(relation, tid, mode))
+ if (!ConditionalLockTupleTuplock(relation, tid, mode,
log_lock_failure))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock
on row in relation \"%s\"",
@@ -7581,7 +7582,8 @@ DoesMultiXactIdConflict(MultiXactId multi, uint16
infomask,
* fail if lock is unavailable. 'rel', 'ctid' and 'oper' are used to set up
* context information for error messages. 'remaining', if not NULL, receives
* the number of members that are still running, including any (non-aborted)
- * subtransactions of our own transaction.
+ * subtransactions of our own transaction. 'logLockFailure' indicates whether
+ * to log details when a lock acquisition fails with 'nowait' enabled.
*
* We do this by sleeping on each member using XactLockTableWait. Any
* members that belong to the current backend are *not* waited for, however;
@@ -7602,7 +7604,7 @@ static bool
Do_MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
uint16 infomask, bool nowait,
Relation rel, ItemPointer ctid, XLTW_Oper
oper,
- int *remaining)
+ int *remaining, bool logLockFailure)
{
bool result = true;
MultiXactMember *members;
@@ -7649,7 +7651,7 @@ Do_MultiXactIdWait(MultiXactId multi, MultiXactStatus
status,
*/
if (nowait)
{
- result = ConditionalXactLockTableWait(memxid);
+ result = ConditionalXactLockTableWait(memxid,
logLockFailure);
if (!result)
break;
}
@@ -7682,7 +7684,7 @@ MultiXactIdWait(MultiXactId multi, MultiXactStatus
status, uint16 infomask,
int *remaining)
{
(void) Do_MultiXactIdWait(multi, status, infomask, false,
- rel, ctid, oper,
remaining);
+ rel, ctid, oper,
remaining, false);
}
/*
@@ -7700,10 +7702,11 @@ MultiXactIdWait(MultiXactId multi, MultiXactStatus
status, uint16 infomask,
*/
static bool
ConditionalMultiXactIdWait(MultiXactId multi, MultiXactStatus status,
- uint16 infomask, Relation
rel, int *remaining)
+ uint16 infomask, Relation
rel, int *remaining,
+ bool logLockFailure)
{
return Do_MultiXactIdWait(multi, status, infomask, true,
- rel, NULL, XLTW_None,
remaining);
+ rel, NULL, XLTW_None,
remaining, logLockFailure);
}
/*
diff --git a/src/backend/access/heap/heapam_handler.c
b/src/backend/access/heap/heapam_handler.c
index e78682c3cef..ca776bea539 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -455,12 +455,12 @@ tuple_lock_retry:
XLTW_FetchUpdated);
break;
case LockWaitSkip:
- if
(!ConditionalXactLockTableWait(SnapshotDirty.xmax))
+ if
(!ConditionalXactLockTableWait(SnapshotDirty.xmax, false))
/* skip
instead of waiting */
return
TM_WouldBlock;
break;
case LockWaitError:
- if
(!ConditionalXactLockTableWait(SnapshotDirty.xmax))
+ if
(!ConditionalXactLockTableWait(SnapshotDirty.xmax, log_lock_failure))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
diff --git a/src/backend/storage/lmgr/lmgr.c b/src/backend/storage/lmgr/lmgr.c
index 68271cb6408..f50962983c3 100644
--- a/src/backend/storage/lmgr/lmgr.c
+++ b/src/backend/storage/lmgr/lmgr.c
@@ -112,7 +112,8 @@ LockRelationOid(Oid relid, LOCKMODE lockmode)
SetLocktagRelationOid(&tag, relid);
- res = LockAcquireExtended(&tag, lockmode, false, false, true,
&locallock);
+ res = LockAcquireExtended(&tag, lockmode, false, false, true,
&locallock,
+ false);
/*
* Now that we have the lock, check for invalidation messages, so that
we
@@ -155,7 +156,8 @@ ConditionalLockRelationOid(Oid relid, LOCKMODE lockmode)
SetLocktagRelationOid(&tag, relid);
- res = LockAcquireExtended(&tag, lockmode, false, true, true,
&locallock);
+ res = LockAcquireExtended(&tag, lockmode, false, true, true, &locallock,
+ false);
if (res == LOCKACQUIRE_NOT_AVAIL)
return false;
@@ -188,7 +190,8 @@ LockRelationId(LockRelId *relid, LOCKMODE lockmode)
SET_LOCKTAG_RELATION(tag, relid->dbId, relid->relId);
- res = LockAcquireExtended(&tag, lockmode, false, false, true,
&locallock);
+ res = LockAcquireExtended(&tag, lockmode, false, false, true,
&locallock,
+ false);
/*
* Now that we have the lock, check for invalidation messages; see notes
@@ -250,7 +253,8 @@ LockRelation(Relation relation, LOCKMODE lockmode)
relation->rd_lockInfo.lockRelId.dbId,
relation->rd_lockInfo.lockRelId.relId);
- res = LockAcquireExtended(&tag, lockmode, false, false, true,
&locallock);
+ res = LockAcquireExtended(&tag, lockmode, false, false, true,
&locallock,
+ false);
/*
* Now that we have the lock, check for invalidation messages; see notes
@@ -281,7 +285,8 @@ ConditionalLockRelation(Relation relation, LOCKMODE
lockmode)
relation->rd_lockInfo.lockRelId.dbId,
relation->rd_lockInfo.lockRelId.relId);
- res = LockAcquireExtended(&tag, lockmode, false, true, true,
&locallock);
+ res = LockAcquireExtended(&tag, lockmode, false, true, true, &locallock,
+ false);
if (res == LOCKACQUIRE_NOT_AVAIL)
return false;
@@ -574,7 +579,8 @@ LockTuple(Relation relation, ItemPointer tid, LOCKMODE
lockmode)
* Returns true iff the lock was acquired.
*/
bool
-ConditionalLockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode)
+ConditionalLockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode,
+ bool logLockFailure)
{
LOCKTAG tag;
@@ -584,7 +590,8 @@ ConditionalLockTuple(Relation relation, ItemPointer tid,
LOCKMODE lockmode)
ItemPointerGetBlockNumber(tid),
ItemPointerGetOffsetNumber(tid));
- return (LockAcquire(&tag, lockmode, false, true) !=
LOCKACQUIRE_NOT_AVAIL);
+ return (LockAcquireExtended(&tag, lockmode, false, true, true, NULL,
+ logLockFailure)
!= LOCKACQUIRE_NOT_AVAIL);
}
/*
@@ -726,7 +733,7 @@ XactLockTableWait(TransactionId xid, Relation rel,
ItemPointer ctid,
* Returns true if the lock was acquired.
*/
bool
-ConditionalXactLockTableWait(TransactionId xid)
+ConditionalXactLockTableWait(TransactionId xid, bool logLockFailure)
{
LOCKTAG tag;
bool first = true;
@@ -738,7 +745,9 @@ ConditionalXactLockTableWait(TransactionId xid)
SET_LOCKTAG_TRANSACTION(tag, xid);
- if (LockAcquire(&tag, ShareLock, false, true) ==
LOCKACQUIRE_NOT_AVAIL)
+ if (LockAcquireExtended(&tag, ShareLock, false, true, true,
NULL,
+ logLockFailure)
+ == LOCKACQUIRE_NOT_AVAIL)
return false;
LockRelease(&tag, ShareLock, false);
@@ -1027,7 +1036,8 @@ ConditionalLockDatabaseObject(Oid classid, Oid objid,
uint16 objsubid,
objid,
objsubid);
- res = LockAcquireExtended(&tag, lockmode, false, true, true,
&locallock);
+ res = LockAcquireExtended(&tag, lockmode, false, true, true, &locallock,
+ false);
if (res == LOCKACQUIRE_NOT_AVAIL)
return false;
@@ -1106,7 +1116,8 @@ ConditionalLockSharedObject(Oid classid, Oid objid,
uint16 objsubid,
objid,
objsubid);
- res = LockAcquireExtended(&tag, lockmode, false, true, true,
&locallock);
+ res = LockAcquireExtended(&tag, lockmode, false, true, true, &locallock,
+ false);
if (res == LOCKACQUIRE_NOT_AVAIL)
return false;
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index ccfe6b69bf5..858a10e4ae4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -39,6 +39,7 @@
#include "access/xlogutils.h"
#include "miscadmin.h"
#include "pg_trace.h"
+#include "storage/lmgr.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "storage/spin.h"
@@ -48,8 +49,9 @@
#include "utils/resowner.h"
-/* This configuration variable is used to set the lock table size */
-int max_locks_per_xact; /* set by guc.c */
+/* GUC variables */
+int max_locks_per_xact; /* used to set the lock table size
*/
+bool log_lock_failure = false;
#define NLOCKENTS() \
mul_size(max_locks_per_xact, add_size(MaxBackends, max_prepared_xacts))
@@ -806,7 +808,7 @@ LockAcquire(const LOCKTAG *locktag,
bool dontWait)
{
return LockAcquireExtended(locktag, lockmode, sessionLock, dontWait,
- true, NULL);
+ true, NULL, false);
}
/*
@@ -822,6 +824,9 @@ LockAcquire(const LOCKTAG *locktag,
*
* If locallockp isn't NULL, *locallockp receives a pointer to the LOCALLOCK
* table entry if a lock is successfully acquired, or NULL if not.
+ *
+ * logLockFailure indicates whether to log details when a lock acquisition
+ * fails with dontWait = true.
*/
LockAcquireResult
LockAcquireExtended(const LOCKTAG *locktag,
@@ -829,7 +834,8 @@ LockAcquireExtended(const LOCKTAG *locktag,
bool sessionLock,
bool dontWait,
bool reportMemoryError,
- LOCALLOCK **locallockp)
+ LOCALLOCK **locallockp,
+ bool logLockFailure)
{
LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
LockMethod lockMethodTable;
@@ -1145,6 +1151,47 @@ LockAcquireExtended(const LOCKTAG *locktag,
if (dontWait)
{
+ /*
+ * Log lock holders and waiters as a detail log message
if
+ * logLockFailure = true and lock acquisition fails
with dontWait
+ * = true
+ */
+ if (logLockFailure)
+ {
+ StringInfoData buf,
+ lock_waiters_sbuf,
+ lock_holders_sbuf;
+ const char *modename;
+ int lockHoldersNum = 0;
+
+ initStringInfo(&buf);
+ initStringInfo(&lock_waiters_sbuf);
+ initStringInfo(&lock_holders_sbuf);
+
+ DescribeLockTag(&buf, &locallock->tag.lock);
+ modename =
GetLockmodeName(locallock->tag.lock.locktag_lockmethodid,
+
lockmode);
+
+ /* Gather a list of all lock holders and
waiters */
+ LWLockAcquire(partitionLock, LW_SHARED);
+ GetLockHoldersAndWaiters(locallock,
&lock_holders_sbuf,
+
&lock_waiters_sbuf, &lockHoldersNum);
+ LWLockRelease(partitionLock);
+
+ ereport(LOG,
+ (errmsg("process %d could not
obtain %s on %s",
+ MyProcPid,
modename, buf.data),
+ errdetail_log_plural(
+
"Process holding the lock: %s, Wait queue: %s.",
+
"Processes holding the lock: %s, Wait queue: %s.",
+
lockHoldersNum,
+
lock_holders_sbuf.data,
+
lock_waiters_sbuf.data)));
+
+ pfree(buf.data);
+ pfree(lock_holders_sbuf.data);
+ pfree(lock_waiters_sbuf.data);
+ }
if (locallockp)
*locallockp = NULL;
return LOCKACQUIRE_NOT_AVAIL;
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 749a79d48ef..e4ca861a8e6 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1514,10 +1514,6 @@ ProcSleep(LOCALLOCK *locallock)
long secs;
int usecs;
long msecs;
- dlist_iter proc_iter;
- PROCLOCK *curproclock;
- bool first_holder = true,
- first_waiter = true;
int lockHoldersNum = 0;
initStringInfo(&buf);
@@ -1533,54 +1529,10 @@ ProcSleep(LOCALLOCK *locallock)
msecs = secs * 1000 + usecs / 1000;
usecs = usecs % 1000;
- /*
- * we loop over the lock's procLocks to gather a list
of all
- * holders and waiters. Thus we will be able to provide
more
- * detailed information for lock debugging purposes.
- *
- * lock->procLocks contains all processes which hold or
wait for
- * this lock.
- */
-
+ /* Gather a list of all lock holders and waiters */
LWLockAcquire(partitionLock, LW_SHARED);
-
- dlist_foreach(proc_iter, &lock->procLocks)
- {
- curproclock =
- dlist_container(PROCLOCK, lockLink,
proc_iter.cur);
-
- /*
- * we are a waiter if myProc->waitProcLock ==
curproclock; we
- * are a holder if it is NULL or something
different
- */
- if (curproclock->tag.myProc->waitProcLock ==
curproclock)
- {
- if (first_waiter)
- {
-
appendStringInfo(&lock_waiters_sbuf, "%d",
-
curproclock->tag.myProc->pid);
- first_waiter = false;
- }
- else
-
appendStringInfo(&lock_waiters_sbuf, ", %d",
-
curproclock->tag.myProc->pid);
- }
- else
- {
- if (first_holder)
- {
-
appendStringInfo(&lock_holders_sbuf, "%d",
-
curproclock->tag.myProc->pid);
- first_holder = false;
- }
- else
-
appendStringInfo(&lock_holders_sbuf, ", %d",
-
curproclock->tag.myProc->pid);
-
- lockHoldersNum++;
- }
- }
-
+ GetLockHoldersAndWaiters(locallock, &lock_holders_sbuf,
+
&lock_waiters_sbuf, &lockHoldersNum);
LWLockRelease(partitionLock);
if (deadlock_state == DS_SOFT_DEADLOCK)
@@ -1885,6 +1837,81 @@ CheckDeadLockAlert(void)
errno = save_errno;
}
+/*
+ * GetLockHoldersAndWaiters - get lock holders and waiters for a lock
+ *
+ * Fill lock_holders_sbuf and lock_waiters_sbuf with the PIDs of processes
holding
+ * and waiting for the lock, and set lockHoldersNum to the number of lock
holders.
+ *
+ * The lock table's partition lock must be held on entry and remains held on
exit.
+ */
+void
+GetLockHoldersAndWaiters(LOCALLOCK *locallock, StringInfo lock_holders_sbuf,
+ StringInfo lock_waiters_sbuf,
int *lockHoldersNum)
+{
+ dlist_iter proc_iter;
+ PROCLOCK *curproclock;
+ LOCK *lock = locallock->lock;
+ bool first_holder = true,
+ first_waiter = true;
+
+#ifdef USE_ASSERT_CHECKING
+ {
+ uint32 hashcode = locallock->hashcode;
+ LWLock *partitionLock = LockHashPartitionLock(hashcode);
+
+ Assert(LWLockHeldByMe(partitionLock));
+ }
+#endif
+
+ *lockHoldersNum = 0;
+
+ /*
+ * Loop over the lock's procLocks to gather a list of all holders and
+ * waiters. Thus we will be able to provide more detailed information
for
+ * lock debugging purposes.
+ *
+ * lock->procLocks contains all processes which hold or wait for this
+ * lock.
+ */
+ dlist_foreach(proc_iter, &lock->procLocks)
+ {
+ curproclock =
+ dlist_container(PROCLOCK, lockLink, proc_iter.cur);
+
+ /*
+ * We are a waiter if myProc->waitProcLock == curproclock; we
are a
+ * holder if it is NULL or something different.
+ */
+ if (curproclock->tag.myProc->waitProcLock == curproclock)
+ {
+ if (first_waiter)
+ {
+ appendStringInfo(lock_waiters_sbuf, "%d",
+
curproclock->tag.myProc->pid);
+ first_waiter = false;
+ }
+ else
+ appendStringInfo(lock_waiters_sbuf, ", %d",
+
curproclock->tag.myProc->pid);
+ }
+ else
+ {
+ if (first_holder)
+ {
+ appendStringInfo(lock_holders_sbuf, "%d",
+
curproclock->tag.myProc->pid);
+ first_holder = false;
+ }
+ else
+ appendStringInfo(lock_holders_sbuf, ", %d",
+
curproclock->tag.myProc->pid);
+
+ (*lockHoldersNum)++;
+ }
+ }
+}
+
/*
* ProcWaitForSignal - wait for a signal from another backend.
*
diff --git a/src/backend/utils/misc/guc_tables.c
b/src/backend/utils/misc/guc_tables.c
index ad25cbb39c5..c0b28bbe783 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -1594,6 +1594,15 @@ struct config_bool ConfigureNamesBool[] =
false,
NULL, NULL, NULL
},
+ {
+ {"log_lock_failure", PGC_SUSET, LOGGING_WHAT,
+ gettext_noop("Logs lock failures."),
+ NULL
+ },
+ &log_lock_failure,
+ false,
+ NULL, NULL, NULL
+ },
{
{"log_recovery_conflict_waits", PGC_SIGHUP, LOGGING_WHAT,
gettext_noop("Logs standby recovery conflict waits."),
diff --git a/src/backend/utils/misc/postgresql.conf.sample
b/src/backend/utils/misc/postgresql.conf.sample
index 2d1de9c37bd..47aedde8cf5 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -608,6 +608,7 @@
# %% = '%'
# e.g. '<%u%%%d> '
#log_lock_waits = off # log lock waits >= deadlock_timeout
+#log_lock_failure = off # log lock failures
#log_recovery_conflict_waits = off # log standby recovery conflict waits
# >= deadlock_timeout
#log_parameter_max_length = -1 # when logging statements, limit logged
diff --git a/src/include/storage/lmgr.h b/src/include/storage/lmgr.h
index 728260c1cc0..58eee4e0d54 100644
--- a/src/include/storage/lmgr.h
+++ b/src/include/storage/lmgr.h
@@ -73,7 +73,7 @@ extern void UnlockPage(Relation relation, BlockNumber blkno,
LOCKMODE lockmode);
/* Lock a tuple (see heap_lock_tuple before assuming you understand this) */
extern void LockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
extern bool ConditionalLockTuple(Relation relation, ItemPointer tid,
- LOCKMODE
lockmode);
+ LOCKMODE
lockmode, bool logLockFailure);
extern void UnlockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
/* Lock an XID (used to wait for a transaction to finish) */
@@ -81,7 +81,8 @@ extern void XactLockTableInsert(TransactionId xid);
extern void XactLockTableDelete(TransactionId xid);
extern void XactLockTableWait(TransactionId xid, Relation rel,
ItemPointer ctid,
XLTW_Oper oper);
-extern bool ConditionalXactLockTableWait(TransactionId xid);
+extern bool ConditionalXactLockTableWait(TransactionId xid,
+
bool logLockFailure);
/* Lock VXIDs, specified by conflicting locktags */
extern void WaitForLockers(LOCKTAG heaplocktag, LOCKMODE lockmode, bool
progress);
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index 1076995518f..5db3809c673 100644
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -30,6 +30,7 @@ typedef struct PGPROC PGPROC;
/* GUC variables */
extern PGDLLIMPORT int max_locks_per_xact;
+extern PGDLLIMPORT bool log_lock_failure;
#ifdef LOCK_DEBUG
extern PGDLLIMPORT int Trace_lock_oidmin;
@@ -560,7 +561,8 @@ extern LockAcquireResult LockAcquireExtended(const LOCKTAG
*locktag,
bool sessionLock,
bool dontWait,
bool reportMemoryError,
-
LOCALLOCK **locallockp);
+
LOCALLOCK **locallockp,
+
bool logLockFailure);
extern void AbortStrongLockAcquire(void);
extern void MarkLockClear(LOCALLOCK *locallock);
extern bool LockRelease(const LOCKTAG *locktag,
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 114eb1f8f76..0750ec3c474 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -489,6 +489,10 @@ extern void ProcWakeup(PGPROC *proc, ProcWaitStatus
waitStatus);
extern void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock);
extern void CheckDeadLockAlert(void);
extern void LockErrorCleanup(void);
+extern void GetLockHoldersAndWaiters(LOCALLOCK *locallock,
+
StringInfo lock_holders_sbuf,
+
StringInfo lock_waiters_sbuf,
+ int
*lockHoldersNum);
extern void ProcWaitForSignal(uint32 wait_event_info);
extern void ProcSendSignal(ProcNumber procNumber);
--
2.48.1
