Avoid palloc(0) when MaxBackends = 1.

tglsfdc · tglsfdc · commit edf497dec96e · 2002-10-03T19:17:55.000Z
diff --git a/src/backend/storage/lmgr/deadlock.c b/src/backend/storage/lmgr/deadlock.c
@@ -12,7 +12,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/deadlock.c,v 1.13 2002/09/04 20:31:25 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/deadlock.c,v 1.14 2002/10/03 19:17:55 tgl Exp $
  *
  *	Interface:
  *
@@ -125,9 +125,11 @@ InitDeadLockChecking(void)
 	 * We need to consider rearranging at most MaxBackends/2 wait queues
 	 * (since it takes at least two waiters in a queue to create a soft
 	 * edge), and the expanded form of the wait queues can't involve more
-	 * than MaxBackends total waiters.
+	 * than MaxBackends total waiters.  (But avoid palloc(0) if
+	 * MaxBackends = 1.)
 	 */
-	waitOrders = (WAIT_ORDER *) palloc((MaxBackends / 2) * sizeof(WAIT_ORDER));
+	waitOrders = (WAIT_ORDER *)
+		palloc(((MaxBackends + 1) / 2) * sizeof(WAIT_ORDER));
 	waitOrderProcs = (PGPROC **) palloc(MaxBackends * sizeof(PGPROC *));
 
 	/*

Original file line number	Diff line number	Diff line change
`@@ -12,7 +12,7 @@`
`12`	`12`	`*`
`13`	`13`	`*`
`14`	`14`	`* IDENTIFICATION`
`15`		`- * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/deadlock.c,v 1.13 2002/09/04 20:31:25 momjian Exp $`
	`15`	`+ * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/deadlock.c,v 1.14 2002/10/03 19:17:55 tgl Exp $`
`16`	`16`	`*`
`17`	`17`	`* Interface:`
`18`	`18`	`*`
`@@ -125,9 +125,11 @@ InitDeadLockChecking(void)`
`125`	`125`	`* We need to consider rearranging at most MaxBackends/2 wait queues`
`126`	`126`	`* (since it takes at least two waiters in a queue to create a soft`
`127`	`127`	`* edge), and the expanded form of the wait queues can't involve more`
`128`		`- * than MaxBackends total waiters.`
	`128`	`+ * than MaxBackends total waiters. (But avoid palloc(0) if`
	`129`	`+ * MaxBackends = 1.)`
`129`	`130`	`*/`
`130`		`- waitOrders = (WAIT_ORDER ) palloc((MaxBackends / 2) sizeof(WAIT_ORDER));`
	`131`	`+ waitOrders = (WAIT_ORDER *)`
	`132`	`+ palloc(((MaxBackends + 1) / 2) * sizeof(WAIT_ORDER));`
`131`	`133`	`waitOrderProcs = (PGPROC *) palloc(MaxBackends sizeof(PGPROC *));`
`132`	`134`
`133`	`135`	`/*`