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Update for deadlock detection.

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This commit is contained in:
Bruce Momjian 1998-12-29 19:32:08 +00:00
parent 06c120e67e
commit 6059c5a141
1 changed files with 29 additions and 18 deletions
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47
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 1.46 1998/12/29 18:36:29 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.47 1998/12/29 19:32:08 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 1.46 1998/12/29 18:36:29 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.47 1998/12/29 19:32:08 momjian Exp $
*/
#include <sys/time.h>
#include <unistd.h>
@ -77,7 +77,7 @@
#include "storage/proc.h"
#include "utils/trace.h"
static void HandleDeadLock(void);
static void HandleDeadLock(int sig);
static PROC *ProcWakeup(PROC *proc, int errType);
#define DeadlockCheckTimer pg_options[OPT_DEADLOCKTIMEOUT]
@ -154,6 +154,8 @@ InitProcess(IPCKey key)
* Routine called if deadlock timer goes off. See ProcSleep()
* ------------------
*/
pqsignal(SIGALRM, HandleDeadLock);
SpinAcquire(ProcStructLock);
/* attach to the free list */
@ -447,8 +449,10 @@ ProcSleep(PROC_QUEUE *waitQueue,/* lock->waitProcs */
TransactionId xid) /* needed by user locks, see below */
{
int i;
bool deadlock_checked = false;
PROC *proc;
bool deadlock_checked = false;
struct itimerval timeval,
dummy;
/*
* If the first entries in the waitQueue have a greater priority than
@ -512,28 +516,27 @@ ProcSleep(PROC_QUEUE *waitQueue,/* lock->waitProcs */
SpinRelease(spinlock);
/* --------------
* We set this so we can wake up after one second to check for a deadlock.
* We set this so we can wake up periodically and check for a deadlock.
* If a deadlock is detected, the handler releases the processes
* semaphore and aborts the current transaction.
*
* Need to zero out struct to set the interval and the micro seconds fields
* to 0.
* --------------
*/
MemSet(&timeval, 0, sizeof(struct itimerval));
timeval.it_value.tv_sec = \
(DeadlockCheckTimer ? DeadlockCheckTimer : DEADLOCK_CHECK_TIMER);
do
{
MyProc->errType = NO_ERROR; /* reset flag after deadlock check */
if (deadlock_checked == false)
{
if (sleep(DeadlockCheckTimer ? DeadlockCheckTimer : DEADLOCK_CHECK_TIMER)
== 0 /* no signal interruption */ )
{
HandleDeadLock();
deadlock_checked = true;
}
}
else
pause();
if (!deadlock_checked)
if (setitimer(ITIMER_REAL, &timeval, &dummy))
elog(FATAL, "ProcSleep: Unable to set timer for process wakeup");
deadlock_checked = true;
/* --------------
* if someone wakes us between SpinRelease and IpcSemaphoreLock,
* IpcSemaphoreLock will not block. The wakeup is "saved" by
@ -545,6 +548,14 @@ ProcSleep(PROC_QUEUE *waitQueue,/* lock->waitProcs */
} while (MyProc->errType == STATUS_NOT_FOUND); /* sleep after deadlock
* check */
/* ---------------
* We were awoken before a timeout - now disable the timer
* ---------------
*/
timeval.it_value.tv_sec = 0;
if (setitimer(ITIMER_REAL, &timeval, &dummy))
elog(FATAL, "ProcSleep: Unable to diable timer for process wakeup");
/* ----------------
* We were assumed to be in a critical section when we went
* to sleep.
@ -687,7 +698,7 @@ ProcAddLock(SHM_QUEUE *elem)
* --------------------
*/
static void
HandleDeadLock()
HandleDeadLock(int sig)
{
LOCK *mywaitlock;