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Back-patch fix to cause stats processes to detach from shared memory,

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so that they do not prevent the postmaster from deleting the shmem segment
during crash recovery.
This commit is contained in:
Tom Lane
2003-11-30 21:56:36 +00:00
parent 8582f21afd
commit a0547f6ea2
3 changed files with 35 additions and 3 deletions
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29
src/backend/port/sysv_shmem.c
View File

@@ -10,7 +10,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/port/sysv_shmem.c,v 1.4 2002/09/04 20:31:24 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/port/sysv_shmem.c,v 1.4.2.1 2003/11/30 21:56:36 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -41,6 +41,9 @@ typedef int IpcMemoryId; /* shared memory ID returned by shmget(2) */
#define IPCProtection (0600) /* access/modify by user only */
static IpcMemoryKey UsedShmemSegID = 0;
static void *UsedShmemSegAddr = NULL;
static void *InternalIpcMemoryCreate(IpcMemoryKey memKey, uint32 size);
static void IpcMemoryDetach(int status, Datum shmaddr);
static void IpcMemoryDelete(int status, Datum shmId);
@@ -395,5 +398,29 @@ PGSharedMemoryCreate(uint32 size, bool makePrivate, int port)
hdr->totalsize = size;
hdr->freeoffset = MAXALIGN(sizeof(PGShmemHeader));
/* Save info for possible future use */
UsedShmemSegAddr = memAddress;
UsedShmemSegID = NextShmemSegID;
return hdr;
}
/*
* PGSharedMemoryDetach
*
* Detach from the shared memory segment, if still attached. This is not
* intended for use by the process that originally created the segment
* (it will have an on_shmem_exit callback registered to do that). Rather,
* this is for subprocesses that have inherited an attachment and want to
* get rid of it.
*/
void
PGSharedMemoryDetach(void)
{
if (UsedShmemSegAddr != NULL)
{
if (shmdt(UsedShmemSegAddr) < 0)
elog(LOG, "shmdt(%p) failed: %m", UsedShmemSegAddr);
UsedShmemSegAddr = NULL;
}
}

6
src/backend/postmaster/pgstat.c
View File

@@ -16,7 +16,7 @@
*
* Copyright (c) 2001, PostgreSQL Global Development Group
*
* $Header: /cvsroot/pgsql/src/backend/postmaster/pgstat.c,v 1.31.2.2 2003/07/22 19:13:25 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/postmaster/pgstat.c,v 1.31.2.3 2003/11/30 21:56:36 tgl Exp $
* ----------
*/
#include "postgres.h"
@@ -42,6 +42,7 @@
#include "utils/memutils.h"
#include "storage/backendid.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
#include "utils/rel.h"
#include "utils/hsearch.h"
#include "utils/ps_status.h"
@@ -324,6 +325,9 @@ pgstat_start(void)
/* Close the postmaster's sockets, except for pgstat link */
ClosePostmasterPorts(false);
/* Drop our connection to postmaster's shared memory, as well */
PGSharedMemoryDetach();
pgstat_main();
exit(0);

3
src/include/storage/pg_shmem.h
View File

@@ -17,7 +17,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: pg_shmem.h,v 1.4 2002/09/04 20:31:45 momjian Exp $
* $Id: pg_shmem.h,v 1.4.2.1 2003/11/30 21:56:36 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -37,5 +37,6 @@ typedef struct PGShmemHeader /* standard header for all Postgres shmem */
extern PGShmemHeader *PGSharedMemoryCreate(uint32 size, bool makePrivate,
int port);
extern bool PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2);
extern void PGSharedMemoryDetach(void);
#endif /* PG_SHMEM_H */