Hi,
Tom Lane írta:
> Boszormenyi Zoltan <[email protected]> writes:
>
>> You expressed stability concerns coming from this patch.
>> Were these concerns because of locks timing out making
>> things fragile or because of general feelings about introducing
>> such a patch at the end of the release cycle? I was thinking
>> about the former, hence this modification.
>>
>
> Indeed, I am *very* concerned about the stability implications of this
> patch. I just don't believe that arbitrarily restricting which
> processes the GUC applies to will make it any safer.
>
> regards, tom lane
>
Okay, here is the rewritten lock_timeout GUC patch that
uses setitimer() to set the timeout for lock timeout.
I removed the GUC assignment/validation function.
I left the current statement timeout vs deadlock timeout logic
mostly intact in enable_sig_alarm(), because it's used by
a few places. The only change is that statement_fin_time is
always computed there because the newly introduced function
(enable_sig_alarm_for_lock_timeout()) checks it to see
whether the lock timeout triggers earlier then the deadlock timeout.
As it was discussed before, this is 9.1 material.
Best regards,
Zoltán Böszörményi
--
Bible has answers for everything. Proof:
"But let your communication be, Yea, yea; Nay, nay: for whatsoever is more
than these cometh of evil." (Matthew 5:37) - basics of digital technology.
"May your kingdom come" - superficial description of plate tectonics
----------------------------------
Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
http://www.postgresql.at/
diff -dcrpN pgsql.orig/doc/src/sgml/config.sgml pgsql/doc/src/sgml/config.sgml
*** pgsql.orig/doc/src/sgml/config.sgml 2010-02-17 10:05:40.000000000 +0100
--- pgsql/doc/src/sgml/config.sgml 2010-02-19 11:29:18.000000000 +0100
*************** COPY postgres_log FROM '/full/path/to/lo
*** 4240,4245 ****
--- 4240,4269 ----
</listitem>
</varlistentry>
+ <varlistentry id="guc-lock-timeout" xreflabel="lock_timeout">
+ <term><varname>lock_timeout</varname> (<type>integer</type>)</term>
+ <indexterm>
+ <primary><varname>lock_timeout</> configuration parameter</primary>
+ </indexterm>
+ <listitem>
+ <para>
+ Abort any statement that tries to acquire a heavy-weight lock (e.g. rows,
+ pages, tables, indices or other objects) and the lock has to wait more
+ than the specified number of milliseconds, starting from the time the
+ command arrives at the server from the client.
+ If <varname>log_min_error_statement</> is set to <literal>ERROR</> or lower,
+ the statement that timed out will also be logged. A value of zero
+ (the default) turns off the limitation.
+ </para>
+
+ <para>
+ Setting <varname>lock_timeout</> in
+ <filename>postgresql.conf</> is not recommended because it
+ affects all sessions.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-vacuum-freeze-table-age" xreflabel="vacuum_freeze_table_age">
<term><varname>vacuum_freeze_table_age</varname> (<type>integer</type>)</term>
<indexterm>
diff -dcrpN pgsql.orig/doc/src/sgml/ref/lock.sgml pgsql/doc/src/sgml/ref/lock.sgml
*** pgsql.orig/doc/src/sgml/ref/lock.sgml 2009-09-18 08:26:40.000000000 +0200
--- pgsql/doc/src/sgml/ref/lock.sgml 2010-02-19 11:29:18.000000000 +0100
*************** LOCK [ TABLE ] [ ONLY ] <replaceable cla
*** 39,46 ****
<literal>NOWAIT</literal> is specified, <command>LOCK
TABLE</command> does not wait to acquire the desired lock: if it
cannot be acquired immediately, the command is aborted and an
! error is emitted. Once obtained, the lock is held for the
! remainder of the current transaction. (There is no <command>UNLOCK
TABLE</command> command; locks are always released at transaction
end.)
</para>
--- 39,49 ----
<literal>NOWAIT</literal> is specified, <command>LOCK
TABLE</command> does not wait to acquire the desired lock: if it
cannot be acquired immediately, the command is aborted and an
! error is emitted. If <varname>lock_timeout</varname> is set to a value
! higher than 0, and the lock cannot be acquired under the specified
! timeout value in milliseconds, the command is aborted and an error
! is emitted. Once obtained, the lock is held for the remainder of
! the current transaction. (There is no <command>UNLOCK
TABLE</command> command; locks are always released at transaction
end.)
</para>
diff -dcrpN pgsql.orig/doc/src/sgml/ref/select.sgml pgsql/doc/src/sgml/ref/select.sgml
*** pgsql.orig/doc/src/sgml/ref/select.sgml 2010-02-13 19:44:33.000000000 +0100
--- pgsql/doc/src/sgml/ref/select.sgml 2010-02-19 11:29:18.000000000 +0100
*************** FOR SHARE [ OF <replaceable class="param
*** 1160,1165 ****
--- 1160,1173 ----
</para>
<para>
+ If <literal>NOWAIT</> option is not specified and <varname>lock_timeout</varname>
+ is set to a value higher than 0, and the lock needs to wait more than
+ the specified value in milliseconds, the command reports an error after
+ timing out, rather than waiting indefinitely. The note in the previous
+ paragraph applies to the <varname>lock_timeout</varname>, too.
+ </para>
+
+ <para>
If specific tables are named in <literal>FOR UPDATE</literal>
or <literal>FOR SHARE</literal>,
then only rows coming from those tables are locked; any other
diff -dcrpN pgsql.orig/src/backend/port/posix_sema.c pgsql/src/backend/port/posix_sema.c
*** pgsql.orig/src/backend/port/posix_sema.c 2010-01-03 12:54:22.000000000 +0100
--- pgsql/src/backend/port/posix_sema.c 2010-02-19 21:21:21.000000000 +0100
***************
*** 24,29 ****
--- 24,30 ----
#include "miscadmin.h"
#include "storage/ipc.h"
#include "storage/pg_sema.h"
+ #include "storage/proc.h"
#ifdef USE_NAMED_POSIX_SEMAPHORES
*************** PGSemaphoreTryLock(PGSemaphore sema)
*** 313,315 ****
--- 314,341 ----
return true;
}
+
+ /*
+ * PGSemaphoreTimedLock
+ *
+ * Lock a semaphore (decrement count), blocking if count would be < 0
+ * Return if lock_timeout expired
+ */
+ void
+ PGSemaphoreTimedLock(PGSemaphore sema, bool interruptOK)
+ {
+ int errStatus;
+
+ do
+ {
+ ImmediateInterruptOK = interruptOK;
+ CHECK_FOR_INTERRUPTS();
+ errStatus = sem_wait(PG_SEM_REF(sema));
+ ImmediateInterruptOK = false;
+ } while (errStatus < 0 && errno == EINTR && !lock_timeout_detected);
+
+ if (lock_timeout_detected)
+ return;
+ if (errStatus < 0)
+ elog(FATAL, "sem_wait failed: %m");
+ }
diff -dcrpN pgsql.orig/src/backend/port/sysv_sema.c pgsql/src/backend/port/sysv_sema.c
*** pgsql.orig/src/backend/port/sysv_sema.c 2010-01-03 12:54:22.000000000 +0100
--- pgsql/src/backend/port/sysv_sema.c 2010-02-19 21:20:17.000000000 +0100
***************
*** 30,35 ****
--- 30,36 ----
#include "miscadmin.h"
#include "storage/ipc.h"
#include "storage/pg_sema.h"
+ #include "storage/proc.h"
#ifndef HAVE_UNION_SEMUN
*************** PGSemaphoreTryLock(PGSemaphore sema)
*** 497,499 ****
--- 498,530 ----
return true;
}
+
+ /*
+ * PGSemaphoreTimedLock
+ *
+ * Lock a semaphore (decrement count), blocking if count would be < 0
+ * Return if lock_timeout expired
+ */
+ void
+ PGSemaphoreTimedLock(PGSemaphore sema, bool interruptOK)
+ {
+ int errStatus;
+ struct sembuf sops;
+
+ sops.sem_op = -1; /* decrement */
+ sops.sem_flg = 0;
+ sops.sem_num = sema->semNum;
+
+ do
+ {
+ ImmediateInterruptOK = interruptOK;
+ CHECK_FOR_INTERRUPTS();
+ errStatus = semop(sema->semId, &sops, 1);
+ ImmediateInterruptOK = false;
+ } while (errStatus < 0 && errno == EINTR && !lock_timeout_detected);
+
+ if (lock_timeout_detected)
+ return;
+ if (errStatus < 0)
+ elog(FATAL, "semop(id=%d) failed: %m", sema->semId);
+ }
diff -dcrpN pgsql.orig/src/backend/port/win32_sema.c pgsql/src/backend/port/win32_sema.c
*** pgsql.orig/src/backend/port/win32_sema.c 2010-01-03 12:54:22.000000000 +0100
--- pgsql/src/backend/port/win32_sema.c 2010-02-19 21:18:52.000000000 +0100
***************
*** 16,21 ****
--- 16,22 ----
#include "miscadmin.h"
#include "storage/ipc.h"
#include "storage/pg_sema.h"
+ #include "storage/proc.h"
static HANDLE *mySemSet; /* IDs of sema sets acquired so far */
static int numSems; /* number of sema sets acquired so far */
*************** PGSemaphoreTryLock(PGSemaphore sema)
*** 205,207 ****
--- 206,263 ----
/* keep compiler quiet */
return false;
}
+
+ /*
+ * PGSemaphoreTimedLock
+ *
+ * Lock a semaphore (decrement count), blocking if count would be < 0.
+ * Serve the interrupt if interruptOK is true.
+ * Return if lock_timeout expired.
+ */
+ void
+ PGSemaphoreTimedLock(PGSemaphore sema, bool interruptOK)
+ {
+ DWORD ret;
+ HANDLE wh[2];
+
+ wh[0] = *sema;
+ wh[1] = pgwin32_signal_event;
+
+ /*
+ * As in other implementations of PGSemaphoreLock, we need to check for
+ * cancel/die interrupts each time through the loop. But here, there is
+ * no hidden magic about whether the syscall will internally service a
+ * signal --- we do that ourselves.
+ */
+ do
+ {
+ ImmediateInterruptOK = interruptOK;
+ CHECK_FOR_INTERRUPTS();
+
+ errno = 0;
+ ret = WaitForMultipleObjectsEx(2, wh, FALSE, INFINITE, TRUE);
+
+ if (ret == WAIT_OBJECT_0)
+ {
+ /* We got it! */
+ return;
+ }
+ else if (ret == WAIT_OBJECT_0 + 1)
+ {
+ /* Signal event is set - we have a signal to deliver */
+ pgwin32_dispatch_queued_signals();
+ errno = EINTR;
+ }
+ else
+ /* Otherwise we are in trouble */
+ errno = EIDRM;
+
+ ImmediateInterruptOK = false;
+ } while (errno == EINTR && !lock_timeout_detected);
+
+ if (lock_timeout_detected)
+ return;
+ if (errno != 0)
+ ereport(FATAL,
+ (errmsg("could not lock semaphore: error code %d", (int) GetLastError())));
+ }
diff -dcrpN pgsql.orig/src/backend/storage/lmgr/lmgr.c pgsql/src/backend/storage/lmgr/lmgr.c
*** pgsql.orig/src/backend/storage/lmgr/lmgr.c 2010-01-03 12:54:25.000000000 +0100
--- pgsql/src/backend/storage/lmgr/lmgr.c 2010-02-19 20:58:51.000000000 +0100
***************
*** 19,26 ****
--- 19,29 ----
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/catalog.h"
+ #include "catalog/pg_database.h"
#include "miscadmin.h"
#include "storage/lmgr.h"
+ #include "utils/lsyscache.h"
+ #include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/inval.h"
*************** LockRelationOid(Oid relid, LOCKMODE lock
*** 78,83 ****
--- 81,101 ----
res = LockAcquire(&tag, lockmode, false, false);
+ if (res == LOCKACQUIRE_NOT_AVAIL)
+ {
+ char *relname = get_rel_name(relid);
+ if (relname)
+ ereport(ERROR,
+ (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+ errmsg("could not obtain lock on relation \"%s\"",
+ relname)));
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+ errmsg("could not obtain lock on relation with OID %u",
+ relid)));
+ }
+
/*
* Now that we have the lock, check for invalidation messages, so that we
* will update or flush any stale relcache entry before we try to use it.
*************** LockRelation(Relation relation, LOCKMODE
*** 173,178 ****
--- 191,202 ----
res = LockAcquire(&tag, lockmode, false, false);
+ if (res == LOCKACQUIRE_NOT_AVAIL)
+ ereport(ERROR,
+ (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+ errmsg("could not obtain lock on relation \"%s\"",
+ RelationGetRelationName(relation))));
+
/*
* Now that we have the lock, check for invalidation messages; see notes
* in LockRelationOid.
*************** LockRelationIdForSession(LockRelId *reli
*** 250,256 ****
SET_LOCKTAG_RELATION(tag, relid->dbId, relid->relId);
! (void) LockAcquire(&tag, lockmode, true, false);
}
/*
--- 274,293 ----
SET_LOCKTAG_RELATION(tag, relid->dbId, relid->relId);
! if (LockAcquire(&tag, lockmode, true, false) == LOCKACQUIRE_NOT_AVAIL)
! {
! char *relname = get_rel_name(relid->relId);
! if (relname)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on relation \"%s\"",
! relname)));
! else
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on relation with OID %u",
! relid->relId)));
! }
}
/*
*************** LockRelationForExtension(Relation relati
*** 285,291 ****
relation->rd_lockInfo.lockRelId.dbId,
relation->rd_lockInfo.lockRelId.relId);
! (void) LockAcquire(&tag, lockmode, false, false);
}
/*
--- 322,332 ----
relation->rd_lockInfo.lockRelId.dbId,
relation->rd_lockInfo.lockRelId.relId);
! if (LockAcquire(&tag, lockmode, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on index \"%s\"",
! RelationGetRelationName(relation))));
}
/*
*************** LockPage(Relation relation, BlockNumber
*** 319,325 ****
relation->rd_lockInfo.lockRelId.relId,
blkno);
! (void) LockAcquire(&tag, lockmode, false, false);
}
/*
--- 360,370 ----
relation->rd_lockInfo.lockRelId.relId,
blkno);
! if (LockAcquire(&tag, lockmode, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on page %u of relation \"%s\"",
! blkno, RelationGetRelationName(relation))));
}
/*
*************** LockTuple(Relation relation, ItemPointer
*** 375,381 ****
ItemPointerGetBlockNumber(tid),
ItemPointerGetOffsetNumber(tid));
! (void) LockAcquire(&tag, lockmode, false, false);
}
/*
--- 420,430 ----
ItemPointerGetBlockNumber(tid),
ItemPointerGetOffsetNumber(tid));
! if (LockAcquire(&tag, lockmode, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on row in relation \"%s\"",
! RelationGetRelationName(relation))));
}
/*
*************** XactLockTableInsert(TransactionId xid)
*** 429,435 ****
SET_LOCKTAG_TRANSACTION(tag, xid);
! (void) LockAcquire(&tag, ExclusiveLock, false, false);
}
/*
--- 478,487 ----
SET_LOCKTAG_TRANSACTION(tag, xid);
! if (LockAcquire(&tag, ExclusiveLock, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on transaction with ID %u", xid)));
}
/*
*************** XactLockTableWait(TransactionId xid)
*** 473,479 ****
SET_LOCKTAG_TRANSACTION(tag, xid);
! (void) LockAcquire(&tag, ShareLock, false, false);
LockRelease(&tag, ShareLock, false);
--- 525,534 ----
SET_LOCKTAG_TRANSACTION(tag, xid);
! if (LockAcquire(&tag, ShareLock, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on transaction with ID %u", xid)));
LockRelease(&tag, ShareLock, false);
*************** VirtualXactLockTableInsert(VirtualTransa
*** 531,537 ****
SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
! (void) LockAcquire(&tag, ExclusiveLock, false, false);
}
/*
--- 586,596 ----
SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
! if (LockAcquire(&tag, ExclusiveLock, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on virtual transaction with ID %u",
! vxid.localTransactionId)));
}
/*
*************** VirtualXactLockTableWait(VirtualTransact
*** 549,555 ****
SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
! (void) LockAcquire(&tag, ShareLock, false, false);
LockRelease(&tag, ShareLock, false);
}
--- 608,618 ----
SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
! if (LockAcquire(&tag, ShareLock, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on virtual transaction with ID %u",
! vxid.localTransactionId)));
LockRelease(&tag, ShareLock, false);
}
*************** LockDatabaseObject(Oid classid, Oid obji
*** 598,604 ****
objid,
objsubid);
! (void) LockAcquire(&tag, lockmode, false, false);
}
/*
--- 661,671 ----
objid,
objsubid);
! if (LockAcquire(&tag, lockmode, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on class:object: %u:%u",
! classid, objid)));
}
/*
*************** LockSharedObject(Oid classid, Oid objid,
*** 636,642 ****
objid,
objsubid);
! (void) LockAcquire(&tag, lockmode, false, false);
/* Make sure syscaches are up-to-date with any changes we waited for */
AcceptInvalidationMessages();
--- 703,713 ----
objid,
objsubid);
! if (LockAcquire(&tag, lockmode, false, false) == LOCKACQUIRE_NOT_AVAIL)
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on class:object: %u:%u",
! classid, objid)));
/* Make sure syscaches are up-to-date with any changes we waited for */
AcceptInvalidationMessages();
*************** LockSharedObjectForSession(Oid classid,
*** 678,684 ****
objid,
objsubid);
! (void) LockAcquire(&tag, lockmode, true, false);
}
/*
--- 749,770 ----
objid,
objsubid);
! if (LockAcquire(&tag, lockmode, true, false) == LOCKACQUIRE_NOT_AVAIL)
! switch(classid)
! {
! case DatabaseRelationId:
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on database with ID %u",
! objid)));
! break;
! default:
! ereport(ERROR,
! (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
! errmsg("could not obtain lock on class:object: %u:%u",
! classid, objid)));
! break;
! }
}
/*
diff -dcrpN pgsql.orig/src/backend/storage/lmgr/lock.c pgsql/src/backend/storage/lmgr/lock.c
*** pgsql.orig/src/backend/storage/lmgr/lock.c 2010-02-01 10:45:49.000000000 +0100
--- pgsql/src/backend/storage/lmgr/lock.c 2010-02-19 11:29:18.000000000 +0100
*************** PROCLOCK_PRINT(const char *where, const
*** 255,261 ****
static uint32 proclock_hash(const void *key, Size keysize);
static void RemoveLocalLock(LOCALLOCK *locallock);
static void GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner);
! static void WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner);
static bool UnGrantLock(LOCK *lock, LOCKMODE lockmode,
PROCLOCK *proclock, LockMethod lockMethodTable);
static void CleanUpLock(LOCK *lock, PROCLOCK *proclock,
--- 255,261 ----
static uint32 proclock_hash(const void *key, Size keysize);
static void RemoveLocalLock(LOCALLOCK *locallock);
static void GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner);
! static int WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner);
static bool UnGrantLock(LOCK *lock, LOCKMODE lockmode,
PROCLOCK *proclock, LockMethod lockMethodTable);
static void CleanUpLock(LOCK *lock, PROCLOCK *proclock,
*************** ProcLockHashCode(const PROCLOCKTAG *proc
*** 451,457 ****
* dontWait: if true, don't wait to acquire lock
*
* Returns one of:
! * LOCKACQUIRE_NOT_AVAIL lock not available, and dontWait=true
* LOCKACQUIRE_OK lock successfully acquired
* LOCKACQUIRE_ALREADY_HELD incremented count for lock already held
*
--- 451,457 ----
* dontWait: if true, don't wait to acquire lock
*
* Returns one of:
! * LOCKACQUIRE_NOT_AVAIL lock not available, either dontWait=true or timeout
* LOCKACQUIRE_OK lock successfully acquired
* LOCKACQUIRE_ALREADY_HELD incremented count for lock already held
*
*************** LockAcquireExtended(const LOCKTAG *lockt
*** 837,843 ****
locktag->locktag_type,
lockmode);
! WaitOnLock(locallock, owner);
TRACE_POSTGRESQL_LOCK_WAIT_DONE(locktag->locktag_field1,
locktag->locktag_field2,
--- 837,843 ----
locktag->locktag_type,
lockmode);
! status = WaitOnLock(locallock, owner);
TRACE_POSTGRESQL_LOCK_WAIT_DONE(locktag->locktag_field1,
locktag->locktag_field2,
*************** LockAcquireExtended(const LOCKTAG *lockt
*** 852,871 ****
* done when the lock was granted to us --- see notes in WaitOnLock.
*/
! /*
! * Check the proclock entry status, in case something in the ipc
! * communication doesn't work correctly.
! */
! if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
{
! PROCLOCK_PRINT("LockAcquire: INCONSISTENT", proclock);
! LOCK_PRINT("LockAcquire: INCONSISTENT", lock, lockmode);
! /* Should we retry ? */
! LWLockRelease(partitionLock);
! elog(ERROR, "LockAcquire failed");
}
- PROCLOCK_PRINT("LockAcquire: granted", proclock);
- LOCK_PRINT("LockAcquire: granted", lock, lockmode);
}
LWLockRelease(partitionLock);
--- 852,883 ----
* done when the lock was granted to us --- see notes in WaitOnLock.
*/
! switch (status)
{
! case STATUS_OK:
! /*
! * Check the proclock entry status, in case something in the ipc
! * communication doesn't work correctly.
! */
! if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
! {
! PROCLOCK_PRINT("LockAcquire: INCONSISTENT", proclock);
! LOCK_PRINT("LockAcquire: INCONSISTENT", lock, lockmode);
! /* Should we retry ? */
! LWLockRelease(partitionLock);
! elog(ERROR, "LockAcquire failed");
! }
! PROCLOCK_PRINT("LockAcquire: granted", proclock);
! LOCK_PRINT("LockAcquire: granted", lock, lockmode);
! break;
! case STATUS_WAITING:
! PROCLOCK_PRINT("LockAcquire: timed out", proclock);
! LOCK_PRINT("LockAcquire: timed out", lock, lockmode);
! break;
! default:
! elog(ERROR, "LockAcquire invalid status");
! break;
}
}
LWLockRelease(partitionLock);
*************** LockAcquireExtended(const LOCKTAG *lockt
*** 891,897 ****
locktag->locktag_field2);
}
! return LOCKACQUIRE_OK;
}
/*
--- 903,909 ----
locktag->locktag_field2);
}
! return (status == STATUS_OK ? LOCKACQUIRE_OK : LOCKACQUIRE_NOT_AVAIL);
}
/*
*************** GrantAwaitedLock(void)
*** 1169,1182 ****
* Caller must have set MyProc->heldLocks to reflect locks already held
* on the lockable object by this process.
*
* The appropriate partition lock must be held at entry.
*/
! static void
WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
{
LOCKMETHODID lockmethodid = LOCALLOCK_LOCKMETHOD(*locallock);
LockMethod lockMethodTable = LockMethods[lockmethodid];
char *volatile new_status = NULL;
LOCK_PRINT("WaitOnLock: sleeping on lock",
locallock->lock, locallock->tag.mode);
--- 1181,1200 ----
* Caller must have set MyProc->heldLocks to reflect locks already held
* on the lockable object by this process.
*
+ * Result: returns value of ProcSleep()
+ * STATUS_OK if we acquired the lock
+ * STATUS_ERROR if not (deadlock)
+ * STATUS_WAITING if not (timeout)
+ *
* The appropriate partition lock must be held at entry.
*/
! static int
WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
{
LOCKMETHODID lockmethodid = LOCALLOCK_LOCKMETHOD(*locallock);
LockMethod lockMethodTable = LockMethods[lockmethodid];
char *volatile new_status = NULL;
+ int wait_status;
LOCK_PRINT("WaitOnLock: sleeping on lock",
locallock->lock, locallock->tag.mode);
*************** WaitOnLock(LOCALLOCK *locallock, Resourc
*** 1218,1225 ****
*/
PG_TRY();
{
! if (ProcSleep(locallock, lockMethodTable) != STATUS_OK)
{
/*
* We failed as a result of a deadlock, see CheckDeadLock(). Quit
* now.
--- 1236,1248 ----
*/
PG_TRY();
{
! wait_status = ProcSleep(locallock, lockMethodTable);
! switch (wait_status)
{
+ case STATUS_OK:
+ case STATUS_WAITING:
+ break;
+ default:
/*
* We failed as a result of a deadlock, see CheckDeadLock(). Quit
* now.
*************** WaitOnLock(LOCALLOCK *locallock, Resourc
*** 1264,1271 ****
pfree(new_status);
}
! LOCK_PRINT("WaitOnLock: wakeup on lock",
locallock->lock, locallock->tag.mode);
}
/*
--- 1287,1300 ----
pfree(new_status);
}
! if (wait_status == STATUS_OK)
! LOCK_PRINT("WaitOnLock: wakeup on lock",
! locallock->lock, locallock->tag.mode);
! else if (wait_status == STATUS_WAITING)
! LOCK_PRINT("WaitOnLock: timeout on lock",
locallock->lock, locallock->tag.mode);
+
+ return wait_status;
}
/*
diff -dcrpN pgsql.orig/src/backend/storage/lmgr/proc.c pgsql/src/backend/storage/lmgr/proc.c
*** pgsql.orig/src/backend/storage/lmgr/proc.c 2010-02-13 19:44:38.000000000 +0100
--- pgsql/src/backend/storage/lmgr/proc.c 2010-02-19 22:38:13.000000000 +0100
***************
*** 52,57 ****
--- 52,59 ----
/* GUC variables */
int DeadlockTimeout = 1000;
int StatementTimeout = 0;
+ int LockTimeout = 0;
+ static int CurrentLockTimeout = 0;
bool log_lock_waits = false;
/* Pointer to this process's PGPROC struct, if any */
*************** static volatile bool statement_timeout_a
*** 79,87 ****
--- 81,92 ----
static volatile bool deadlock_timeout_active = false;
static volatile DeadLockState deadlock_state = DS_NOT_YET_CHECKED;
volatile bool cancel_from_timeout = false;
+ static volatile bool lock_timeout_active = false;
+ volatile bool lock_timeout_detected = false;
/* timeout_start_time is set when log_lock_waits is true */
static TimestampTz timeout_start_time;
+ static TimestampTz timeout_fin_time;
/* statement_fin_time is valid only if statement_timeout_active is true */
static TimestampTz statement_fin_time;
*************** static void ProcKill(int code, Datum arg
*** 92,97 ****
--- 97,103 ----
static void AuxiliaryProcKill(int code, Datum arg);
static bool CheckStatementTimeout(void);
static bool CheckStandbyTimeout(void);
+ static bool enable_sig_alarm_for_lock_timeout(int delayms);
/*
*************** ProcQueueInit(PROC_QUEUE *queue)
*** 795,801 ****
* The lock table's partition lock must be held at entry, and will be held
* at exit.
*
! * Result: STATUS_OK if we acquired the lock, STATUS_ERROR if not (deadlock).
*
* ASSUME: that no one will fiddle with the queue until after
* we release the partition lock.
--- 801,810 ----
* The lock table's partition lock must be held at entry, and will be held
* at exit.
*
! * Result:
! * STATUS_OK if we acquired the lock
! * STATUS_ERROR if not (deadlock)
! * STATUS_WAITING if not (timeout)
*
* ASSUME: that no one will fiddle with the queue until after
* we release the partition lock.
*************** ProcSleep(LOCALLOCK *locallock, LockMeth
*** 949,955 ****
elog(FATAL, "could not set timer for process wakeup");
/*
! * If someone wakes us between LWLockRelease and PGSemaphoreLock,
* PGSemaphoreLock will not block. The wakeup is "saved" by the semaphore
* implementation. While this is normally good, there are cases where a
* saved wakeup might be leftover from a previous operation (for example,
--- 958,973 ----
elog(FATAL, "could not set timer for process wakeup");
/*
! * Reset timer so we are awaken in case of lock timeout.
! * This doesn't modify the timer for deadlock check in case
! * the deadlock check happens earlier.
! */
! CurrentLockTimeout = LockTimeout;
! if (!enable_sig_alarm_for_lock_timeout(CurrentLockTimeout))
! elog(FATAL, "could not set timer for process wakeup");
!
! /*
! * If someone wakes us between LWLockRelease and PGSemaphoreTimedLock,
* PGSemaphoreLock will not block. The wakeup is "saved" by the semaphore
* implementation. While this is normally good, there are cases where a
* saved wakeup might be leftover from a previous operation (for example,
*************** ProcSleep(LOCALLOCK *locallock, LockMeth
*** 967,973 ****
*/
do
{
! PGSemaphoreLock(&MyProc->sem, true);
/*
* waitStatus could change from STATUS_WAITING to something else
--- 985,994 ----
*/
do
{
! PGSemaphoreTimedLock(&MyProc->sem, true);
!
! if (lock_timeout_detected == true)
! break;
/*
* waitStatus could change from STATUS_WAITING to something else
*************** ProcSleep(LOCALLOCK *locallock, LockMeth
*** 1107,1112 ****
--- 1128,1141 ----
LWLockAcquire(partitionLock, LW_EXCLUSIVE);
/*
+ * If we're in timeout, so we're not waiting anymore and
+ * we're not the one that the lock will be granted to.
+ * So remove ourselves from the wait queue.
+ */
+ if (lock_timeout_detected)
+ RemoveFromWaitQueue(MyProc, hashcode);
+
+ /*
* We no longer want LockWaitCancel to do anything.
*/
lockAwaited = NULL;
*************** ProcSleep(LOCALLOCK *locallock, LockMeth
*** 1120,1127 ****
/*
* We don't have to do anything else, because the awaker did all the
* necessary update of the lock table and MyProc.
*/
! return MyProc->waitStatus;
}
--- 1149,1158 ----
/*
* We don't have to do anything else, because the awaker did all the
* necessary update of the lock table and MyProc.
+ * RemoveFromWaitQueue() have set MyProc->waitStatus = STATUS_ERROR,
+ * we need to distinguish this case.
*/
! return (lock_timeout_detected ? STATUS_WAITING : MyProc->waitStatus);
}
*************** enable_sig_alarm(int delayms, bool is_st
*** 1460,1477 ****
* than normal, but that does no harm.
*/
timeout_start_time = GetCurrentTimestamp();
! fin_time = TimestampTzPlusMilliseconds(timeout_start_time, delayms);
deadlock_timeout_active = true;
! if (fin_time >= statement_fin_time)
return true;
}
else
{
/* Begin deadlock timeout with no statement-level timeout */
deadlock_timeout_active = true;
! /* GetCurrentTimestamp can be expensive, so only do it if we must */
! if (log_lock_waits)
! timeout_start_time = GetCurrentTimestamp();
}
/* If we reach here, okay to set the timer interrupt */
--- 1491,1553 ----
* than normal, but that does no harm.
*/
timeout_start_time = GetCurrentTimestamp();
! timeout_fin_time = TimestampTzPlusMilliseconds(timeout_start_time, delayms);
deadlock_timeout_active = true;
! if (timeout_fin_time >= statement_fin_time)
return true;
}
else
{
/* Begin deadlock timeout with no statement-level timeout */
deadlock_timeout_active = true;
! /*
! * Computing the timeout_fin_time is needed because
! * the lock timeout logic checks for it.
! */
! timeout_start_time = GetCurrentTimestamp();
! timeout_fin_time = TimestampTzPlusMilliseconds(timeout_start_time, delayms);
! }
!
! /* If we reach here, okay to set the timer interrupt */
! MemSet(&timeval, 0, sizeof(struct itimerval));
! timeval.it_value.tv_sec = delayms / 1000;
! timeval.it_value.tv_usec = (delayms % 1000) * 1000;
! if (setitimer(ITIMER_REAL, &timeval, NULL))
! return false;
! return true;
! }
!
! /*
! * Enable the SIGALRM interrupt to fire after the specified delay
! * in case LockTimeout is set.
! *
! * This code properly handles nesting of lock_timeout timeout alarm
! * within deadlock timeout and statement timeout alarms.
! *
! * Returns TRUE if okay, FALSE on failure.
! */
! static bool
! enable_sig_alarm_for_lock_timeout(int delayms)
! {
! struct itimerval timeval;
! TimestampTz fin_time;
!
! lock_timeout_detected = false;
! if (LockTimeout == 0)
! return true;
!
! fin_time = GetCurrentTimestamp();
! fin_time = TimestampTzPlusMilliseconds(fin_time, delayms);
!
! if (statement_timeout_active)
! {
! if (fin_time > statement_fin_time)
! return true;
! }
! else if (deadlock_timeout_active)
! {
! if (fin_time > timeout_fin_time)
! return true;
}
/* If we reach here, okay to set the timer interrupt */
*************** enable_sig_alarm(int delayms, bool is_st
*** 1480,1485 ****
--- 1556,1563 ----
timeval.it_value.tv_usec = (delayms % 1000) * 1000;
if (setitimer(ITIMER_REAL, &timeval, NULL))
return false;
+
+ lock_timeout_active = true;
return true;
}
*************** disable_sig_alarm(bool is_statement_time
*** 1500,1506 ****
*
* We will re-enable the interrupt if necessary in CheckStatementTimeout.
*/
! if (statement_timeout_active || deadlock_timeout_active)
{
struct itimerval timeval;
--- 1578,1584 ----
*
* We will re-enable the interrupt if necessary in CheckStatementTimeout.
*/
! if (statement_timeout_active || deadlock_timeout_active || lock_timeout_active)
{
struct itimerval timeval;
*************** handle_sig_alarm(SIGNAL_ARGS)
*** 1600,1605 ****
--- 1678,1689 ----
{
int save_errno = errno;
+ if (lock_timeout_active)
+ {
+ lock_timeout_active = false;
+ lock_timeout_detected = true;
+ }
+
if (deadlock_timeout_active)
{
deadlock_timeout_active = false;
*************** handle_sig_alarm(SIGNAL_ARGS)
*** 1609,1614 ****
--- 1693,1710 ----
if (statement_timeout_active)
(void) CheckStatementTimeout();
+ /*
+ * If we got here, the DeadlockTimeout already triggered and found no deadlock.
+ * If LockTimeout is set, and it's greater than DeadlockTimeout,
+ * then retry with a (LockTimeout - DeadlockTimeout) timeout value.
+ */
+ if (!lock_timeout_detected && CurrentLockTimeout && CurrentLockTimeout > DeadlockTimeout)
+ {
+ CurrentLockTimeout -= DeadlockTimeout;
+ if (!enable_sig_alarm_for_lock_timeout(CurrentLockTimeout))
+ elog(FATAL, "could not set timer for process wakeup");
+ }
+
errno = save_errno;
}
diff -dcrpN pgsql.orig/src/backend/utils/misc/guc.c pgsql/src/backend/utils/misc/guc.c
*** pgsql.orig/src/backend/utils/misc/guc.c 2010-02-17 10:05:47.000000000 +0100
--- pgsql/src/backend/utils/misc/guc.c 2010-02-19 13:32:28.000000000 +0100
*************** static struct config_int ConfigureNamesI
*** 1585,1590 ****
--- 1585,1600 ----
},
{
+ {"lock_timeout", PGC_USERSET, CLIENT_CONN_STATEMENT,
+ gettext_noop("Sets the maximum allowed timeout for any lock taken by a statement."),
+ gettext_noop("A value of 0 turns off the timeout."),
+ GUC_UNIT_MS
+ },
+ &LockTimeout,
+ 0, 0, INT_MAX, NULL, NULL
+ },
+
+ {
{"vacuum_freeze_min_age", PGC_USERSET, CLIENT_CONN_STATEMENT,
gettext_noop("Minimum age at which VACUUM should freeze a table row."),
NULL
diff -dcrpN pgsql.orig/src/backend/utils/misc/postgresql.conf.sample pgsql/src/backend/utils/misc/postgresql.conf.sample
*** pgsql.orig/src/backend/utils/misc/postgresql.conf.sample 2010-02-17 10:05:47.000000000 +0100
--- pgsql/src/backend/utils/misc/postgresql.conf.sample 2010-02-19 11:29:19.000000000 +0100
***************
*** 481,486 ****
--- 481,489 ----
#------------------------------------------------------------------------------
#deadlock_timeout = 1s
+ #lock_timeout = 0 # timeout value for heavy-weight locks
+ # taken by statements. 0 disables timeout
+ # unit in milliseconds, default is 0
#max_locks_per_transaction = 64 # min 10
# (change requires restart)
# Note: Each lock table slot uses ~270 bytes of shared memory, and there are
diff -dcrpN pgsql.orig/src/include/storage/pg_sema.h pgsql/src/include/storage/pg_sema.h
*** pgsql.orig/src/include/storage/pg_sema.h 2010-01-03 12:54:39.000000000 +0100
--- pgsql/src/include/storage/pg_sema.h 2010-02-19 21:17:27.000000000 +0100
*************** extern void PGSemaphoreUnlock(PGSemaphor
*** 80,83 ****
--- 80,86 ----
/* Lock a semaphore only if able to do so without blocking */
extern bool PGSemaphoreTryLock(PGSemaphore sema);
+ /* Lock a semaphore (decrement count), blocking if count would be < 0 */
+ extern void PGSemaphoreTimedLock(PGSemaphore sema, bool interruptOK);
+
#endif /* PG_SEMA_H */
diff -dcrpN pgsql.orig/src/include/storage/proc.h pgsql/src/include/storage/proc.h
*** pgsql.orig/src/include/storage/proc.h 2010-02-13 19:44:42.000000000 +0100
--- pgsql/src/include/storage/proc.h 2010-02-19 21:16:32.000000000 +0100
*************** typedef struct PROC_HDR
*** 163,170 ****
--- 163,172 ----
/* configurable options */
extern int DeadlockTimeout;
extern int StatementTimeout;
+ extern int LockTimeout;
extern bool log_lock_waits;
+ extern volatile bool lock_timeout_detected;
extern volatile bool cancel_from_timeout;
--
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