database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-08 11:42:09 +03:00
Code Activity

Clean up backend-exit-time cleanup behavior. Use on_shmem_exit callbacks

Browse Source 
to ensure that we have released buffer refcounts and so forth, rather than
putting ad-hoc operations before (some of the calls to) proc_exit.  Add
commentary to discourage future hackers from repeating that mistake.
This commit is contained in:
Tom Lane
2000-12-18 00:44:50 +00:00
parent 8c8ed4f456
commit a626b78c89
14 changed files with 255 additions and 139 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
src/backend/storage/buffer/buf_init.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/buf_init.c,v 1.39 2000/11/30 01:39:07 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/buf_init.c,v 1.40 2000/12/18 00:44:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -36,6 +36,9 @@
#include "utils/hsearch.h"
#include "utils/memutils.h"
static void ShutdownBufferPoolAccess(void);
/*
* if BMTRACE is defined, we trace the last 200 buffer allocations and
* deallocations in a circular buffer in shared memory.
@ -73,7 +76,7 @@ bool *BufferDirtiedByMe; /* T if buf has been dirtied in cur xact */
* Two important notes. First, the buffer has to be
* available for lookup BEFORE an IO begins. Otherwise
* a second process trying to read the buffer will
* allocate its own copy and the buffeer pool will
* allocate its own copy and the buffer pool will
* become inconsistent.
*
* Buffer Replacement:
@ -126,10 +129,10 @@ long int LocalBufferFlushCount;
/*
* Initialize module: called once during shared-memory initialization
* Initialize shared buffer pool
*
* should calculate size of pool dynamically based on the
* amount of available memory.
* This is called once during shared-memory initialization (either in the
* postmaster, or in a standalone backend).
*/
void
InitBufferPool(void)
@ -144,6 +147,10 @@ InitBufferPool(void)
Lookup_List_Descriptor = Data_Descriptors + 1;
Num_Descriptors = Data_Descriptors + 1;
/*
* It's probably not really necessary to grab the lock --- if there's
* anyone else attached to the shmem at this point, we've got problems.
*/
SpinAcquire(BufMgrLock);
#ifdef BMTRACE
@ -203,12 +210,28 @@ InitBufferPool(void)
BufferDescriptors[Data_Descriptors - 1].freeNext = 0;
}
/* Init the rest of the module */
/* Init other shared buffer-management stuff */
InitBufTable();
InitFreeList(!foundDescs);
SpinRelease(BufMgrLock);
}
/*
* Initialize access to shared buffer pool
*
* This is called during backend startup (whether standalone or under the
* postmaster). It sets up for this backend's access to the already-existing
* buffer pool.
*/
void
InitBufferPoolAccess(void)
{
int i;
/*
* Allocate and zero local arrays of per-buffer info.
*/
BufferBlockPointers = (Block *) calloc(NBuffers, sizeof(Block));
PrivateRefCount = (long *) calloc(NBuffers, sizeof(long));
BufferLocks = (bits8 *) calloc(NBuffers, sizeof(bits8));
@ -224,6 +247,27 @@ InitBufferPool(void)
{
BufferBlockPointers[i] = (Block) MAKE_PTR(BufferDescriptors[i].data);
}
/*
* Now that buffer access is initialized, set up a callback to shut it
* down again at backend exit.
*/
on_shmem_exit(ShutdownBufferPoolAccess, 0);
}
/*
* Shut down buffer manager at backend exit.
*
* This is needed mainly to ensure that we don't leave any buffer reference
* counts set during an error exit.
*/
static void
ShutdownBufferPoolAccess(void)
{
/* Release any buffer context locks we are holding */
UnlockBuffers();
/* Release any buffer reference counts we are holding */
ResetBufferPool(false);
}
/* -----------------------------------------------------