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/*-------------------------------------------------------------------------
*
* bufmgr.h
* POSTGRES buffer manager definitions.
*
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: bufmgr.h,v 1.69 2003/08/04 02:40:14 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef BUFMGR_H
#define BUFMGR_H
#include "access/xlogdefs.h"
#include "storage/buf.h"
#include "storage/lock.h"
#include "storage/relfilenode.h"
#include "utils/rel.h"
typedef void *Block;
/* in globals.c ... this duplicates miscadmin.h */
extern DLLIMPORT int NBuffers;
/* in bufmgr.c */
extern bool zero_damaged_pages;
/* in buf_init.c */
extern DLLIMPORT Block *BufferBlockPointers;
extern long *PrivateRefCount;
/* in localbuf.c */
extern DLLIMPORT int NLocBuffer;
extern DLLIMPORT Block *LocalBufferBlockPointers;
extern long *LocalRefCount;
/* special pageno for bget */
#define P_NEW InvalidBlockNumber /* grow the file to get a new page */
/*
* Buffer context lock modes
*/
#define BUFFER_LOCK_UNLOCK 0
#define BUFFER_LOCK_SHARE 1
#define BUFFER_LOCK_EXCLUSIVE 2
/*
* These routines are beaten on quite heavily, hence the macroization.
*/
#define BAD_BUFFER_ID(bid) ((bid) < 1 || (bid) > NBuffers)
#define INVALID_DESCRIPTOR (-3)
#define UnlockAndReleaseBuffer(buffer) \
( \
LockBuffer(buffer, BUFFER_LOCK_UNLOCK), \
ReleaseBuffer(buffer) \
)
#define UnlockAndWriteBuffer(buffer) \
( \
LockBuffer(buffer, BUFFER_LOCK_UNLOCK), \
WriteBuffer(buffer) \
)
/*
* BufferIsValid
* True iff the given buffer number is valid (either as a shared
* or local buffer).
*
* Note: For a long time this was defined the same as BufferIsPinned,
* that is it would say False if you didn't hold a pin on the buffer.
* I believe this was bogus and served only to mask logic errors.
* Code should always know whether it has a buffer reference,
* independently of the pin state.
*/
#define BufferIsValid(bufnum) \
( \
BufferIsLocal(bufnum) ? \
((bufnum) >= -NLocBuffer) \
: \
(! BAD_BUFFER_ID(bufnum)) \
)
/*
* BufferIsPinned
* True iff the buffer is pinned (also checks for valid buffer number).
*
* NOTE: what we check here is that *this* backend holds a pin on
* the buffer. We do not care whether some other backend does.
*/
#define BufferIsPinned(bufnum) \
( \
BufferIsLocal(bufnum) ? \
((bufnum) >= -NLocBuffer && LocalRefCount[-(bufnum) - 1] > 0) \
: \
( \
BAD_BUFFER_ID(bufnum) ? \
false \
: \
(PrivateRefCount[(bufnum) - 1] > 0) \
) \
)
/*
* IncrBufferRefCount
* Increment the pin count on a buffer that we have *already* pinned
* at least once.
*
* This macro cannot be used on a buffer we do not have pinned,
* because it doesn't change the shared buffer state. Therefore the
* Assert checks are for refcount > 0. Someone got this wrong once...
*/
#define IncrBufferRefCount(buffer) \
( \
BufferIsLocal(buffer) ? \
( \
(void) AssertMacro((buffer) >= -NLocBuffer), \
(void) AssertMacro(LocalRefCount[-(buffer) - 1] > 0), \
(void) LocalRefCount[-(buffer) - 1]++ \
) \
: \
( \
(void) AssertMacro(!BAD_BUFFER_ID(buffer)), \
(void) AssertMacro(PrivateRefCount[(buffer) - 1] > 0), \
(void) PrivateRefCount[(buffer) - 1]++ \
) \
)
/*
* BufferGetBlock
* Returns a reference to a disk page image associated with a buffer.
*
* Note:
* Assumes buffer is valid.
*/
#define BufferGetBlock(buffer) \
( \
AssertMacro(BufferIsValid(buffer)), \
BufferIsLocal(buffer) ? \
LocalBufferBlockPointers[-(buffer) - 1] \
: \
BufferBlockPointers[(buffer) - 1] \
)
/*
* prototypes for functions in bufmgr.c
*/
extern Buffer ReadBuffer(Relation reln, BlockNumber blockNum);
extern int ReleaseBuffer(Buffer buffer);
extern void WriteBuffer(Buffer buffer);
extern void WriteNoReleaseBuffer(Buffer buffer);
extern Buffer ReleaseAndReadBuffer(Buffer buffer, Relation relation,
BlockNumber blockNum);
extern void InitBufferPool(void);
extern void InitBufferPoolAccess(void);
extern char *ShowBufferUsage(void);
extern void ResetBufferUsage(void);
extern void AtEOXact_Buffers(bool isCommit);
extern void FlushBufferPool(void);
extern BlockNumber BufferGetBlockNumber(Buffer buffer);
extern BlockNumber RelationGetNumberOfBlocks(Relation relation);
extern void RelationUpdateNumberOfBlocks(Relation relation);
extern int FlushRelationBuffers(Relation rel, BlockNumber firstDelBlock);
extern void DropRelationBuffers(Relation rel);
extern void DropRelFileNodeBuffers(RelFileNode rnode, bool istemp);
extern void DropBuffers(Oid dbid);
#ifdef NOT_USED
extern void PrintPinnedBufs(void);
#endif
extern int BufferShmemSize(void);
extern RelFileNode BufferGetFileNode(Buffer buffer);
extern void SetBufferCommitInfoNeedsSave(Buffer buffer);
extern void UnlockBuffers(void);
extern void LockBuffer(Buffer buffer, int mode);
extern void LockBufferForCleanup(Buffer buffer);
extern void AbortBufferIO(void);
extern void BufmgrCommit(void);
extern void BufferSync(void);
extern void InitLocalBuffer(void);
#endif
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