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

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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.
This commit is contained in:
Tom Lane 2001-11-06 00:38:26 +00:00
parent 0053cebea5
commit ca7578d454
2 changed files with 11 additions and 6 deletions
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9
src/backend/storage/lmgr/proc.c
View File

@ -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 */

8
src/include/storage/proc.h
View File

@ -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
{