mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Hi, Bruce!

Browse Source 
These are my last changes to lmgr fixing deadlock handling.
Please apply them to cvs...

Vadim
This commit is contained in:
Bruce Momjian 1999-05-13 15:55:45 +00:00
parent 9bbc1657a1
commit 564842a617
4 changed files with 193 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

243
src/backend/storage/lmgr/lock.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.51 1999/05/10 00:45:43 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.52 1999/05/13 15:55:44 momjian Exp $
*
* NOTES
* Outside modules can create a lock table and acquire/release
@ -83,9 +83,9 @@ static int WaitOnLock(LOCKMETHOD lockmethod, LOCK *lock, LOCKMODE lockmode);
#define LOCK_PRINT_AUX(where,lock,type) \
TPRINTF(TRACE_ALL, \
"%s: lock(%x) tbl(%d) rel(%u) db(%d) obj(%u) mask(%x) " \
"hold(%d,%d,%d,%d,%d)=%d " \
"act(%d,%d,%d,%d,%d)=%d wait(%d) type(%s)", \
"%s: lock(%x) tbl(%d) rel(%u) db(%u) obj(%u) mask(%x) " \
"hold(%d,%d,%d,%d,%d,%d,%d)=%d " \
"act(%d,%d,%d,%d,%d,%d,%d)=%d wait(%d) type(%s)", \
where, \
MAKE_OFFSET(lock), \
lock->tag.lockmethod, \
@ -98,12 +98,16 @@ static int WaitOnLock(LOCKMETHOD lockmethod, LOCK *lock, LOCKMODE lockmode);
lock->holders[3], \
lock->holders[4], \
lock->holders[5], \
lock->holders[6], \
lock->holders[7], \
lock->nHolding, \
lock->activeHolders[1], \
lock->activeHolders[2], \
lock->activeHolders[3], \
lock->activeHolders[4], \
lock->activeHolders[5], \
lock->activeHolders[6], \
lock->activeHolders[7], \
lock->nActive, \
lock->waitProcs.size, \
lock_types[type])
@ -119,8 +123,8 @@ static int WaitOnLock(LOCKMETHOD lockmethod, LOCK *lock, LOCKMODE lockmode);
#define XID_PRINT_AUX(where,xidentP) \
TPRINTF(TRACE_ALL, \
"%s: xid(%x) lock(%x) tbl(%d) pid(%d) xid(%d) " \
"hold(%d,%d,%d,%d,%d)=%d", \
"%s: xid(%x) lock(%x) tbl(%d) pid(%d) xid(%u) " \
"hold(%d,%d,%d,%d,%d,%d,%d)=%d", \
where, \
MAKE_OFFSET(xidentP), \
xidentP->tag.lock, \
@ -132,6 +136,8 @@ static int WaitOnLock(LOCKMETHOD lockmethod, LOCK *lock, LOCKMODE lockmode);
xidentP->holders[3], \
xidentP->holders[4], \
xidentP->holders[5], \
xidentP->holders[6], \
xidentP->holders[7], \
xidentP->nHolding)
#else /* !LOCK_MGR_DEBUG */
@ -1561,19 +1567,26 @@ LockingDisabled()
* We have already locked the master lock before being called.
*/
bool
DeadLockCheck(SHM_QUEUE *lockQueue, LOCK *findlock, bool skip_check)
DeadLockCheck(void *proc, LOCK *findlock)
{
int done;
XIDLookupEnt *xidLook = NULL;
XIDLookupEnt *tmp = NULL;
PROC *thisProc = (PROC*) proc,
*waitProc;
SHM_QUEUE *lockQueue = &(thisProc->lockQueue);
SHMEM_OFFSET end = MAKE_OFFSET(lockQueue);
LOCK *lock;
PROC_QUEUE *waitQueue;
int i,
j;
bool first_run = (thisProc == MyProc),
done;
static PROC *checked_procs[MAXBACKENDS];
static int nprocs;
/* initialize at start of recursion */
if (skip_check)
if (first_run)
{
checked_procs[0] = MyProc;
nprocs = 1;
@ -1593,74 +1606,186 @@ DeadLockCheck(SHM_QUEUE *lockQueue, LOCK *findlock, bool skip_check)
LOCK_PRINT("DeadLockCheck", lock, 0);
if (lock->tag.relId == 0) /* user' lock */
goto nxtl;
/*
* This is our only check to see if we found the lock we want.
*
* The lock we are waiting for is already in MyProc->lockQueue so we
* need to skip it here. We are trying to find it in someone
* else's lockQueue. bjm
* waitLock is always in lockQueue of waiting proc,
* if !first_run then upper caller will handle waitProcs
* queue of waitLock.
*/
if (lock == findlock && !skip_check)
return true;
if (thisProc->waitLock == lock && !first_run)
goto nxtl;
/*
* If we found proc holding findlock and sleeping on some my
* other lock then we have to check does it block me or
* another waiters.
*/
if (lock == findlock && !first_run)
{
PROC_QUEUE *waitQueue = &(lock->waitProcs);
PROC *proc;
int i;
int j;
LOCKMETHODCTL *lockctl =
LockMethodTable[DEFAULT_LOCKMETHOD]->ctl;
int lm;
proc = (PROC *) MAKE_PTR(waitQueue->links.prev);
for (i = 0; i < waitQueue->size; i++)
Assert(xidLook->nHolding > 0);
for (lm = 1; lm <= lockctl->numLockModes; lm++)
{
if (xidLook->holders[lm] > 0 &&
lockctl->conflictTab[lm] & findlock->waitMask)
return true;
}
/*
* Else - get the next lock from thisProc's lockQueue
*/
goto nxtl;
}
waitQueue = &(lock->waitProcs);
waitProc = (PROC *) MAKE_PTR(waitQueue->links.prev);
for (i = 0; i < waitQueue->size; i++)
{
if (waitProc == thisProc)
{
Assert(waitProc->waitLock == lock);
Assert(waitProc == MyProc);
waitProc = (PROC *) MAKE_PTR(waitProc->links.prev);
continue;
}
if (lock == findlock) /* first_run also true */
{
LOCKMETHODCTL *lockctl =
LockMethodTable[DEFAULT_LOCKMETHOD]->ctl;
/*
* If I hold some locks on findlock and another proc
* waits on it holding locks too - check if we are
* waiting one another.
* If me blocked by his holdlock...
*/
if (proc != MyProc &&
lock == findlock && /* skip_check also true */
MyProc->holdLock)
if (lockctl->conflictTab[MyProc->token] & waitProc->holdLock)
{
/* and he blocked by me -> deadlock */
if (lockctl->conflictTab[waitProc->token] & MyProc->holdLock)
return true;
/* we shouldn't look at lockQueue of our blockers */
waitProc = (PROC *) MAKE_PTR(waitProc->links.prev);
continue;
}
/*
* If he isn't blocked by me and we request non-conflicting
* lock modes - no deadlock here because of he isn't
* blocked by me in any sence (explicitle or implicitly).
* Note that we don't do like test if !first_run
* (when thisProc is holder and non-waiter on lock) and so
* we call DeadLockCheck below for every waitProc in
* thisProc->lockQueue, even for waitProc-s un-blocked
* by thisProc. Should we? This could save us some time...
*/
if (!(lockctl->conflictTab[waitProc->token] & MyProc->holdLock) &&
!(lockctl->conflictTab[waitProc->token] & (1 << MyProc->token)))
{
waitProc = (PROC *) MAKE_PTR(waitProc->links.prev);
continue;
}
}
/*
* Look in lockQueue of this waitProc, if didn't do this before.
*/
for (j = 0; j < nprocs; j++)
{
if (checked_procs[j] == waitProc)
break;
}
if (j >= nprocs)
{
Assert(nprocs < MAXBACKENDS);
checked_procs[nprocs++] = waitProc;
if (DeadLockCheck(waitProc, findlock))
{
LOCKMETHODCTL *lockctl =
LockMethodTable[DEFAULT_LOCKMETHOD]->ctl;
int holdLock;
Assert(skip_check);
if (lockctl->conflictTab[MyProc->token] & proc->holdLock &&
lockctl->conflictTab[proc->token] & MyProc->holdLock)
return true;
}
/*
* No sense in looking at the wait queue of the lock we
* are looking for. If lock == findlock, and I got here,
* skip_check must be true too.
*/
if (lock != findlock)
{
for (j = 0; j < nprocs; j++)
if (checked_procs[j] == proc)
break;
if (j >= nprocs && lock != findlock)
/*
* Ok, but is waitProc waiting for me (thisProc) ?
*/
if (thisProc->waitLock == lock)
{
Assert(nprocs < MAXBACKENDS);
checked_procs[nprocs++] = proc;
/*
* For non-MyProc entries, we are looking only
* waiters, not necessarily people who already
* hold locks and are waiting. Now we check for
* cases where we have two or more tables in a
* deadlock. We do this by continuing to search
* for someone holding a lock bjm
*/
if (DeadLockCheck(&(proc->lockQueue), findlock, false))
return true;
Assert(first_run);
holdLock = thisProc->holdLock;
}
else /* should we cache holdLock ? */
{
int lm, tmpMask = 2;
Assert(xidLook->nHolding > 0);
for (holdLock = 0, lm = 1;
lm <= lockctl->numLockModes;
lm++, tmpMask <<= 1)
{
if (xidLook->holders[lm] > 0)
holdLock |= tmpMask;
}
Assert(holdLock != 0);
}
if (lockctl->conflictTab[waitProc->token] & holdLock)
{
/*
* Last attempt to avoid deadlock - try to wakeup
* myself.
*/
if (first_run)
{
if (LockResolveConflicts(DEFAULT_LOCKMETHOD,
MyProc->waitLock,
MyProc->token,
MyProc->xid,
NULL) == STATUS_OK)
{
GrantLock(MyProc->waitLock, MyProc->token);
(MyProc->waitLock->waitProcs.size)--;
ProcWakeup(MyProc, NO_ERROR);
return false;
}
}
return true;
}
/*
* Hell! Is he blocked by any (other) holder ?
*/
if (LockResolveConflicts(DEFAULT_LOCKMETHOD,
lock,
waitProc->token,
waitProc->xid,
NULL) != STATUS_OK)
{
/*
* Blocked by others - no deadlock...
*/
#ifdef DEADLOCK_DEBUG
LOCK_PRINT("DeadLockCheck: blocked by others",
lock, waitProc->token);
#endif
waitProc = (PROC *) MAKE_PTR(waitProc->links.prev);
continue;
}
/*
* Well - wakeup this guy! This is the case of
* implicit blocking: thisProc blocked someone who blocked
* waitProc by the fact that he (someone) is already
* waiting for lock (we do this for anti-starving).
*/
GrantLock(lock, waitProc->token);
waitQueue->size--;
waitProc = ProcWakeup(waitProc, NO_ERROR);
continue;
}
proc = (PROC *) MAKE_PTR(proc->links.prev);
}
waitProc = (PROC *) MAKE_PTR(waitProc->links.prev);
}
nxtl:;
if (done)
break;
SHMQueueFirst(&xidLook->queue, (Pointer *) &tmp, &tmp->queue);

11
src/backend/storage/lmgr/proc.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.54 1999/05/07 01:23:04 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.55 1999/05/13 15:55:44 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -46,7 +46,7 @@
* This is so that we can support more backends. (system-wide semaphore
* sets run out pretty fast.) -ay 4/95
*
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.54 1999/05/07 01:23:04 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.55 1999/05/13 15:55:44 momjian Exp $
*/
#include <sys/time.h>
#include <unistd.h>
@ -78,7 +78,6 @@
#include "utils/trace.h"
static void HandleDeadLock(int sig);
static PROC *ProcWakeup(PROC *proc, int errType);
static void ProcFreeAllSemaphores(void);
#define DeadlockCheckTimer pg_options[OPT_DEADLOCKTIMEOUT]
@ -640,7 +639,7 @@ rt:;
* remove the process from the wait queue and set its links invalid.
* RETURN: the next process in the wait queue.
*/
static PROC *
PROC *
ProcWakeup(PROC *proc, int errType)
{
PROC *retProc;
@ -806,10 +805,10 @@ HandleDeadLock(int sig)
DumpAllLocks();
#endif
if (!DeadLockCheck(&(MyProc->lockQueue), MyProc->waitLock, true))
MyProc->errType = STATUS_NOT_FOUND;
if (!DeadLockCheck(MyProc, MyProc->waitLock))
{
UnlockLockTable();
MyProc->errType = STATUS_NOT_FOUND;
return;
}

5
src/include/storage/lock.h
View File

@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: lock.h,v 1.25 1999/05/07 01:23:07 vadim Exp $
* $Id: lock.h,v 1.26 1999/05/13 15:55:44 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -249,8 +249,7 @@ extern void GrantLock(LOCK *lock, LOCKMODE lockmode);
extern bool LockReleaseAll(LOCKMETHOD lockmethod, SHM_QUEUE *lockQueue);
extern int LockShmemSize(int maxBackends);
extern bool LockingDisabled(void);
extern bool DeadLockCheck(SHM_QUEUE *lockQueue, LOCK *findlock,
bool skip_check);
extern bool DeadLockCheck(void *proc, LOCK *findlock);
#ifdef DEADLOCK_DEBUG
extern void DumpLocks(void);

3
src/include/storage/proc.h
View File

@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: proc.h,v 1.21 1999/05/07 01:23:07 vadim Exp $
* $Id: proc.h,v 1.22 1999/05/13 15:55:45 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -119,6 +119,7 @@ extern bool ProcRemove(int pid);
extern void ProcQueueInit(PROC_QUEUE *queue);
extern int ProcSleep(PROC_QUEUE *queue, LOCKMETHODCTL *lockctl, int token,
LOCK *lock);
extern PROC *ProcWakeup(PROC *proc, int errType);
extern int ProcLockWakeup(PROC_QUEUE *queue, LOCKMETHOD lockmethod,
LOCK *lock);
extern void ProcAddLock(SHM_QUEUE *elem);