Oops, I had managed to break query-cancel-while-waiting-for-lock.

src/backend/storage/lmgr/proc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.93 2001/01/16 06:11:34 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.94 2001/01/16 20:59:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,7 +48,7 @@
  *		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 1.93 2001/01/16 06:11:34 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.94 2001/01/16 20:59:34 tgl Exp $
  */
 #include "postgres.h"
 
@@ -353,16 +353,19 @@ RemoveFromWaitQueue(PROC *proc)
 /*
  * Cancel any pending wait for lock, when aborting a transaction.
  *
+ * Returns true if we had been waiting for a lock, else false.
+ *
  * (Normally, this would only happen if we accept a cancel/die
  * interrupt while waiting; but an elog(ERROR) while waiting is
  * within the realm of possibility, too.)
  */
-void
+bool
 LockWaitCancel(void)
 {
 	/* Nothing to do if we weren't waiting for a lock */
 	if (!waitingForLock)
-		return;
+		return false;
+
 	waitingForLock = false;
 
 	/* Turn off the deadlock timer, if it's still running (see ProcSleep) */
@@ -395,6 +398,12 @@ LockWaitCancel(void)
 	 * prematurely.
 	 */
 	ZeroProcSemaphore(MyProc);
+
+	/*
+	 * Return true even if we were kicked off the lock before we were
+	 * able to remove ourselves.
+	 */
+	return true;
 }
 
 

src/backend/tcop/postgres.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.201 2001/01/14 05:08:16 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.202 2001/01/16 20:59:34 tgl Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -940,11 +940,14 @@ die(SIGNAL_ARGS)
 		InterruptPending = true;
 		ProcDiePending = true;
 		/*
-		 * If we're waiting for input, service the interrupt immediately
+		 * If it's safe to interrupt, and we're waiting for input or a lock,
+		 * service the interrupt immediately
 		 */
 		if (ImmediateInterruptOK && CritSectionCount == 0)
 		{
 			DisableNotifyInterrupt();
+			/* Make sure HandleDeadLock won't run while shutting down... */
+			LockWaitCancel();
 			ProcessInterrupts();
 		}
 	}
@@ -967,8 +970,16 @@ QueryCancelHandler(SIGNAL_ARGS)
 		InterruptPending = true;
 		QueryCancelPending = true;
 		/*
-		 * No point in raising Cancel if we are waiting for input ...
+		 * If it's safe to interrupt, and we're waiting for a lock,
+		 * service the interrupt immediately.  No point in interrupting
+		 * if we're waiting for input, however.
 		 */
+		if (ImmediateInterruptOK && CritSectionCount == 0 &&
+			LockWaitCancel())
+		{
+			DisableNotifyInterrupt();
+			ProcessInterrupts();
+		}
 	}
 
 	errno = save_errno;
@@ -1668,7 +1679,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[], const cha
 	if (!IsUnderPostmaster)
 	{
 		puts("\nPOSTGRES backend interactive interface ");
-		puts("$Revision: 1.201 $ $Date: 2001/01/14 05:08:16 $\n");
+		puts("$Revision: 1.202 $ $Date: 2001/01/16 20:59:34 $\n");
 	}
 
 	/*

src/include/storage/proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: proc.h,v 1.35 2001/01/16 06:11:34 tgl Exp $
+ * $Id: proc.h,v 1.36 2001/01/16 20:59:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -140,7 +140,7 @@ extern PROC *ProcWakeup(PROC *proc, int errType);
 extern int ProcLockWakeup(LOCKMETHOD lockmethod, LOCK *lock);
 extern void ProcAddLock(SHM_QUEUE *elem);
 extern void ProcReleaseSpins(PROC *proc);
-extern void LockWaitCancel(void);
+extern bool LockWaitCancel(void);
 extern void HandleDeadLock(SIGNAL_ARGS);
 
 #endif	 /* PROC_H */