The extra semaphore that proc.c now allocates for checkpoint processes

should be accounted for in the PROC_SEM_MAP_ENTRIES() macro.  Otherwise
the ports that rely on this macro to size data structures are broken.
Mea culpa.

Author: tglsfdc

src/backend/storage/lmgr/proc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.114 2001/10/28 06:25:50 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.115 2001/11/06 00:38:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -124,10 +124,13 @@ InitProcGlobal(int maxBackends)
 
 	/*
 	 * Compute size for ProcGlobal structure.  Note we need one more sema
-	 * besides those used for regular backends.
+	 * besides those used for regular backends; this is accounted for in
+	 * the PROC_SEM_MAP_ENTRIES macro.  (We do it that way so that other
+	 * modules that use PROC_SEM_MAP_ENTRIES(maxBackends) to size data
+	 * structures don't have to know about this explicitly.)
 	 */
 	Assert(maxBackends > 0);
-	semMapEntries = PROC_SEM_MAP_ENTRIES(maxBackends + 1);
+	semMapEntries = PROC_SEM_MAP_ENTRIES(maxBackends);
 	procGlobalSize = sizeof(PROC_HDR) + (semMapEntries - 1) *sizeof(SEM_MAP_ENTRY);
 
 	/* Create or attach to the ProcGlobal shared structure */

src/include/storage/proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: proc.h,v 1.53 2001/11/05 17:46:35 momjian Exp $
+ * $Id: proc.h,v 1.54 2001/11/06 00:38:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -93,10 +93,12 @@ extern PROC *MyProc;
  * in each set for identification purposes.)
  *
  * PROC_SEM_MAP_ENTRIES is the number of semaphore sets we need to allocate
- * to keep track of up to maxBackends backends.
+ * to keep track of up to maxBackends backends.  Note that we need one extra
+ * semaphore (see storage/lmgr/proc.c), so the computation may look wrong,
+ * but it's right.
  */
 #define  PROC_NSEMS_PER_SET		16
-#define  PROC_SEM_MAP_ENTRIES(maxBackends)	(((maxBackends)-1)/PROC_NSEMS_PER_SET+1)
+#define  PROC_SEM_MAP_ENTRIES(maxBackends)	((maxBackends)/PROC_NSEMS_PER_SET+1)
 
 typedef struct
 {