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/*-------------------------------------------------------------------------
*
* buf_internals.h--
* Internal definitions.
*
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: buf_internals.h,v 1.21 1998/02/26 04:43:21 momjian Exp $
*
* NOTE
* If BUFFERPAGE0 is defined, then 0 will be used as a
* valid buffer page number.
*
*-------------------------------------------------------------------------
*/
#ifndef BUFMGR_INTERNALS_H
#define BUFMGR_INTERNALS_H
#include <storage/lmgr.h>
#include <storage/buf.h>
/* Buf Mgr constants */
/* in bufmgr.c */
extern int NBuffers;
extern int Data_Descriptors;
extern int Free_List_Descriptor;
extern int Lookup_List_Descriptor;
extern int Num_Descriptors;
/*
* Flags for buffer descriptors
*/
#define BM_DIRTY (1 << 0)
#define BM_PRIVATE (1 << 1)
#define BM_VALID (1 << 2)
#define BM_DELETED (1 << 3)
#define BM_FREE (1 << 4)
#define BM_IO_IN_PROGRESS (1 << 5)
#define BM_IO_ERROR (1 << 6)
#define BM_JUST_DIRTIED (1 << 7)
typedef bits16 BufFlags;
typedef struct sbufdesc BufferDesc;
typedef struct sbufdesc BufferHdr;
typedef struct buftag BufferTag;
/* long * so alignment will be correct */
typedef long **BufferBlock;
struct buftag
{
LRelId relId;
BlockNumber blockNum; /* blknum relative to begin of reln */
};
#define CLEAR_BUFFERTAG(a)\
(a)->relId.dbId = InvalidOid; \
(a)->relId.relId = InvalidOid; \
(a)->blockNum = InvalidBlockNumber
#define INIT_BUFFERTAG(a,xx_reln,xx_blockNum) \
{ \
(a)->blockNum = xx_blockNum;\
(a)->relId = RelationGetLRelId(xx_reln); \
}
#ifdef NOT_USED
#define COPY_BUFFERTAG(a,b)\
{ \
(a)->blockNum = (b)->blockNum;\
LRelIdAssign(*(a),*(b));\
}
#define EQUAL_BUFFERTAG(a,b) \
(((a)->blockNum == (b)->blockNum) &&\
(OID_Equal((a)->relId.relId,(b)->relId.relId)))
#endif
#define BAD_BUFFER_ID(bid) ((bid<1) || (bid>(NBuffers)))
#define INVALID_DESCRIPTOR (-3)
/*
* bletch hack -- anyplace that we declare space for relation or
* database names, we just use '16', not a symbolic constant, to
* specify their lengths. BM_NAMESIZE is the length of these names,
* and is used in the buffer manager code. somebody with lots of
* spare time should do this for all the other modules, too.
*/
#define BM_NAMESIZE 16
/*
* struct sbufdesc -- shared buffer cache metadata for a single
* shared buffer descriptor.
*
* We keep the name of the database and relation in which this
* buffer appears in order to avoid a catalog lookup on cache
* flush if we don't have the reldesc in the cache. It is also
* possible that the relation to which this buffer belongs is
* not visible to all backends at the time that it gets flushed.
* Dbname, relname, dbid, and relid are enough to determine where
* to put the buffer, for all storage managers.
*/
#define PADDED_SBUFDESC_SIZE 128
/* DO NOT CHANGE THIS NEXT STRUCTURE:
It is used only to get padding information for the real sbufdesc structure
It should match the sbufdesc structure exactly except for a missing sb_pad
*/
struct sbufdesc_unpadded
{
Buffer freeNext;
Buffer freePrev;
SHMEM_OFFSET data;
BufferTag tag;
int buf_id;
BufFlags flags;
unsigned refcount;
#ifdef HAS_TEST_AND_SET
slock_t io_in_progress_lock;
#endif /* HAS_TEST_AND_SET */
char sb_dbname[NAMEDATALEN];
/* NOTE NO PADDING OF THE MEMBER HERE */
char sb_relname[NAMEDATALEN];
};
/* THE REAL STRUCTURE - the structure above must match it, minus sb_pad */
struct sbufdesc
{
Buffer freeNext; /* link for freelist chain */
Buffer freePrev;
SHMEM_OFFSET data; /* pointer to data in buf pool */
/* tag and id must be together for table lookup to work */
BufferTag tag; /* file/block identifier */
int buf_id; /* maps global desc to local desc */
BufFlags flags; /* described below */
unsigned refcount; /* # of times buffer is pinned */
#ifdef HAS_TEST_AND_SET
/* can afford a dedicated lock if test-and-set locks are available */
slock_t io_in_progress_lock;
#endif /* HAS_TEST_AND_SET */
char sb_dbname[NAMEDATALEN]; /* name of db in which buf belongs */
/*
* I padded this structure to a power of 2 (PADDED_SBUFDESC_SIZE)
* because BufferDescriptorGetBuffer is called a billion times and it
* does an C pointer subtraction (i.e., "x - y" -> array index of x
* relative to y, which is calculated using division by struct size).
* Integer ".div" hits you for 35 cycles, as opposed to a 1-cycle
* "sra" ... this hack cut 10% off of the time to create the Wisconsin
* database! It eats up more shared memory, of course, but we're
* (allegedly) going to make some of these types bigger soon anyway...
* -pma 1/2/93
*/
/*
* please, don't take the sizeof() this member and use it for
* something important
*/
char sb_relname[NAMEDATALEN + /* name of reln */
PADDED_SBUFDESC_SIZE - sizeof(struct sbufdesc_unpadded)];
};
/*
* mao tracing buffer allocation
*/
/*#define BMTRACE*/
#ifdef BMTRACE
typedef struct _bmtrace
{
int bmt_pid;
long bmt_buf;
long bmt_dbid;
long bmt_relid;
int bmt_blkno;
int bmt_op;
#define BMT_NOTUSED 0
#define BMT_ALLOCFND 1
#define BMT_ALLOCNOTFND 2
#define BMT_DEALLOC 3
} bmtrace;
#endif /* BMTRACE */
/*
* Bufmgr Interface:
*/
/* Internal routines: only called by buf.c */
/*freelist.c*/
extern void AddBufferToFreelist(BufferDesc *bf);
extern void PinBuffer(BufferDesc *buf);
extern void PinBuffer_Debug(char *file, int line, BufferDesc *buf);
extern void UnpinBuffer(BufferDesc *buf);
extern BufferDesc *GetFreeBuffer(void);
extern void InitFreeList(bool init);
/* buf_table.c */
extern void InitBufTable(void);
extern BufferDesc *BufTableLookup(BufferTag *tagPtr);
extern bool BufTableDelete(BufferDesc *buf);
extern bool BufTableInsert(BufferDesc *buf);
/* bufmgr.c */
extern BufferDesc *BufferDescriptors;
extern BufferBlock BufferBlocks;
extern long *PrivateRefCount;
extern long *LastRefCount;
extern long *CommitInfoNeedsSave;
extern SPINLOCK BufMgrLock;
/* localbuf.c */
extern long *LocalRefCount;
extern BufferDesc *LocalBufferDescriptors;
extern int NLocBuffer;
extern BufferDesc *
LocalBufferAlloc(Relation reln, BlockNumber blockNum,
bool *foundPtr);
extern int WriteLocalBuffer(Buffer buffer, bool release);
extern int FlushLocalBuffer(Buffer buffer, bool release);
extern void InitLocalBuffer(void);
extern void LocalBufferSync(void);
extern void ResetLocalBufferPool(void);
#endif /* BUFMGR_INTERNALS_H */
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