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Fix LMGR for MVCC.

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Get rid of Extend lock mode.
This commit is contained in:
Vadim B. Mikheev
1999-05-07 01:23:11 +00:00
parent 86bc1da262
commit 122abf3af3
7 changed files with 207 additions and 219 deletions
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132
src/backend/storage/lmgr/proc.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.53 1999/04/30 02:04:51 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.54 1999/05/07 01:23:04 vadim 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 1.53 1999/04/30 02:04:51 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.54 1999/05/07 01:23:04 vadim Exp $
*/
#include <sys/time.h>
#include <unistd.h>
@ -106,6 +106,8 @@ static void ProcKill(int exitStatus, int pid);
static void ProcGetNewSemKeyAndNum(IPCKey *key, int *semNum);
static void ProcFreeSem(IpcSemaphoreKey semKey, int semNum);
static char *DeadLockMessage = "Deadlock detected -- See the lock(l) manual page for a possible cause.";
/*
* InitProcGlobal -
* initializes the global process table. We put it here so that
@ -488,68 +490,80 @@ ProcQueueInit(PROC_QUEUE *queue)
*/
int
ProcSleep(PROC_QUEUE *waitQueue,/* lock->waitProcs */
SPINLOCK spinlock,
LOCKMETHODCTL *lockctl,
int token, /* lockmode */
int prio,
LOCK *lock,
TransactionId xid) /* needed by user locks, see below */
LOCK *lock)
{
int i;
SPINLOCK spinlock = lockctl->masterLock;
PROC *proc;
int myMask = (1 << token);
int waitMask = lock->waitMask;
int aheadHolders[MAX_LOCKMODES];
bool selfConflict = (lockctl->conflictTab[token] & myMask),
prevSame = false;
bool deadlock_checked = false;
struct itimerval timeval,
dummy;
/*
* If the first entries in the waitQueue have a greater priority than
* we have, we must be a reader, and they must be a writers, and we
* must be here because the current holder is a writer or a reader but
* we don't share shared locks if a writer is waiting. We put
* ourselves after the writers. This way, we have a FIFO, but keep
* the readers together to give them decent priority, and no one
* starves. Because we group all readers together, a non-empty queue
* only has a few possible configurations:
*
* [readers] [writers] [readers][writers] [writers][readers]
* [writers][readers][writers]
*
* In a full queue, we would have a reader holding a lock, then a writer
* gets the lock, then a bunch of readers, made up of readers who
* could not share the first readlock because a writer was waiting,
* and new readers arriving while the writer had the lock. bjm
*/
proc = (PROC *) MAKE_PTR(waitQueue->links.prev);
/* If we are a reader, and they are writers, skip past them */
for (i = 0; i < waitQueue->size && proc->prio > prio; i++)
proc = (PROC *) MAKE_PTR(proc->links.prev);
/* The rest of the queue is FIFO, with readers first, writers last */
for (; i < waitQueue->size && proc->prio <= prio; i++)
proc = (PROC *) MAKE_PTR(proc->links.prev);
MyProc->prio = prio;
MyProc->token = token;
MyProc->waitLock = lock;
#ifdef USER_LOCKS
/* -------------------
* Currently, we only need this for the ProcWakeup routines.
* This must be 0 for user lock, so we can't just use the value
* from GetCurrentTransactionId().
* -------------------
*/
TransactionIdStore(xid, &MyProc->xid);
#else
#ifndef LowLevelLocking
/* -------------------
* currently, we only need this for the ProcWakeup routines
* -------------------
*/
TransactionIdStore((TransactionId) GetCurrentTransactionId(), &MyProc->xid);
#endif
#endif
proc = (PROC *) MAKE_PTR(waitQueue->links.prev);
/* if we don't conflict with any waiter - be first in queue */
if (!(lockctl->conflictTab[token] & waitMask))
goto ins;
for (i = 1; i < MAX_LOCKMODES; i++)
aheadHolders[i] = lock->activeHolders[i];
(aheadHolders[token])++;
for (i = 0; i < waitQueue->size; i++)
{
/* am I waiting for him ? */
if (lockctl->conflictTab[token] & proc->holdLock)
{
/* is he waiting for me ? */
if (lockctl->conflictTab[proc->token] & MyProc->holdLock)
{
MyProc->errType = STATUS_ERROR;
elog(NOTICE, DeadLockMessage);
goto rt;
}
/* being waiting for him - go past */
}
/* if he waits for me */
else if (lockctl->conflictTab[proc->token] & MyProc->holdLock)
{
break;
}
/* if conflicting locks requested */
else if (lockctl->conflictTab[proc->token] & myMask)
{
/*
* If I request non self-conflicting lock and there
* are others requesting the same lock just before me -
* stay here.
*/
if (!selfConflict && prevSame)
break;
}
/*
* Last attempt to don't move any more: if we don't conflict
* with rest waiters in queue.
*/
else if (!(lockctl->conflictTab[token] & waitMask))
break;
prevSame = (proc->token == token);
(aheadHolders[proc->token])++;
if (aheadHolders[proc->token] == lock->holders[proc->token])
waitMask &= ~ (1 << proc->token);
proc = (PROC *) MAKE_PTR(proc->links.prev);
}
ins:;
/* -------------------
* assume that these two operations are atomic (because
* of the spinlock).
@ -558,6 +572,7 @@ ProcSleep(PROC_QUEUE *waitQueue,/* lock->waitProcs */
SHMQueueInsertTL(&(proc->links), &(MyProc->links));
waitQueue->size++;
lock->waitMask |= myMask;
SpinRelease(spinlock);
/* --------------
@ -608,6 +623,8 @@ ProcSleep(PROC_QUEUE *waitQueue,/* lock->waitProcs */
*/
SpinAcquire(spinlock);
rt:;
#ifdef LOCK_MGR_DEBUG
/* Just to get meaningful debug messages from DumpLocks() */
MyProc->waitLock = (LOCK *) NULL;
@ -655,9 +672,9 @@ int
ProcLockWakeup(PROC_QUEUE *queue, LOCKMETHOD lockmethod, LOCK *lock)
{
PROC *proc;
int count;
int count = 0;
int trace_flag;
int last_locktype = -1;
int last_locktype = 0;
int queue_size = queue->size;
Assert(queue->size >= 0);
@ -666,7 +683,6 @@ ProcLockWakeup(PROC_QUEUE *queue, LOCKMETHOD lockmethod, LOCK *lock)
return STATUS_NOT_FOUND;
proc = (PROC *) MAKE_PTR(queue->links.prev);
count = 0;
while ((queue_size--) && (proc))
{
@ -678,7 +694,7 @@ ProcLockWakeup(PROC_QUEUE *queue, LOCKMETHOD lockmethod, LOCK *lock)
continue;
/*
* This proc conflicts with locks held by others, ignored.
* Does this proc conflict with locks held by others ?
*/
if (LockResolveConflicts(lockmethod,
lock,
@ -686,6 +702,8 @@ ProcLockWakeup(PROC_QUEUE *queue, LOCKMETHOD lockmethod, LOCK *lock)
proc->xid,
(XIDLookupEnt *) NULL) != STATUS_OK)
{
if (count != 0)
break;
last_locktype = proc->token;
continue;
}
@ -828,7 +846,7 @@ HandleDeadLock(int sig)
*/
UnlockLockTable();
elog(NOTICE, "Deadlock detected -- See the lock(l) manual page for a possible cause.");
elog(NOTICE, DeadLockMessage);
return;
}