1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/*-------------------------------------------------------------------------
*
* buf_internals.h
* Internal definitions for buffer manager and the buffer replacement
* strategy.
*
*
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/storage/buf_internals.h,v 1.75.4.1 2005/02/03 23:30:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef BUFMGR_INTERNALS_H
#define BUFMGR_INTERNALS_H
#include "storage/backendid.h"
#include "storage/buf.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
#include "utils/rel.h"
/*
* Flags for buffer descriptors
*/
#define BM_DIRTY (1 << 0) /* data needs writing */
#define BM_VALID (1 << 1) /* data is valid */
#define BM_IO_IN_PROGRESS (1 << 2) /* read or write in
* progress */
#define BM_IO_ERROR (1 << 3) /* previous I/O failed */
#define BM_JUST_DIRTIED (1 << 4) /* dirtied since write
* started */
#define BM_PIN_COUNT_WAITER (1 << 5) /* have waiter for sole
* pin */
typedef bits16 BufFlags;
/*
* Buffer tag identifies which disk block the buffer contains.
*
* Note: the BufferTag data must be sufficient to determine where to write the
* block, without reference to pg_class or pg_tablespace entries. It's
* possible that the backend flushing the buffer doesn't even believe the
* relation is visible yet (its xact may have started before the xact that
* created the rel). The storage manager must be able to cope anyway.
*
* Note: if there's any pad bytes in the struct, INIT_BUFFERTAG will have
* to be fixed to zero them, since this struct is used as a hash key.
*/
typedef struct buftag
{
RelFileNode rnode; /* physical relation identifier */
BlockNumber blockNum; /* blknum relative to begin of reln */
} BufferTag;
#define CLEAR_BUFFERTAG(a) \
( \
(a).rnode.spcNode = InvalidOid, \
(a).rnode.dbNode = InvalidOid, \
(a).rnode.relNode = InvalidOid, \
(a).blockNum = InvalidBlockNumber \
)
#define INIT_BUFFERTAG(a,xx_reln,xx_blockNum) \
( \
(a).rnode = (xx_reln)->rd_node, \
(a).blockNum = (xx_blockNum) \
)
#define BUFFERTAGS_EQUAL(a,b) \
( \
RelFileNodeEquals((a).rnode, (b).rnode) && \
(a).blockNum == (b).blockNum \
)
/*
* BufferDesc -- shared descriptor/state data for a single shared buffer.
*/
typedef struct sbufdesc
{
Buffer bufNext; /* link in freelist chain */
SHMEM_OFFSET data; /* pointer to data in buf pool */
/* tag and id must be together for table lookup (still true?) */
BufferTag tag; /* file/block identifier */
int buf_id; /* buffer's index number (from 0) */
BufFlags flags; /* see bit definitions above */
unsigned refcount; /* # of backends holding pins on buffer */
LWLockId io_in_progress_lock; /* to wait for I/O to complete */
LWLockId cntx_lock; /* to lock access to page context */
bool cntxDirty; /* new way to mark block as dirty */
/*
* We can't physically remove items from a disk page if another
* backend has the buffer pinned. Hence, a backend may need to wait
* for all other pins to go away. This is signaled by storing its own
* backend ID into wait_backend_id and setting flag bit
* BM_PIN_COUNT_WAITER. At present, there can be only one such waiter
* per buffer.
*/
BackendId wait_backend_id; /* backend ID of pin-count waiter */
} BufferDesc;
#define BufferDescriptorGetBuffer(bdesc) ((bdesc)->buf_id + 1)
/* in bufmgr.c */
extern BufferDesc *BufferDescriptors;
/* in localbuf.c */
extern BufferDesc *LocalBufferDescriptors;
/* counters in buf_init.c */
extern long int ReadBufferCount;
extern long int ReadLocalBufferCount;
extern long int BufferHitCount;
extern long int LocalBufferHitCount;
extern long int BufferFlushCount;
extern long int LocalBufferFlushCount;
/*
* Internal routines: only called by bufmgr
*/
/* freelist.c */
extern BufferDesc *StrategyBufferLookup(BufferTag *tagPtr, bool recheck,
int *cdb_found_index);
extern BufferDesc *StrategyGetBuffer(int *cdb_replace_index);
extern void StrategyReplaceBuffer(BufferDesc *buf, BufferTag *newTag,
int cdb_found_index, int cdb_replace_index);
extern void StrategyInvalidateBuffer(BufferDesc *buf);
extern void StrategyHintVacuum(bool vacuum_active);
extern int StrategyDirtyBufferList(BufferDesc **buffers, BufferTag *buftags,
int max_buffers);
extern int StrategyShmemSize(void);
extern void StrategyInitialize(bool init);
/* buf_table.c */
extern int BufTableShmemSize(int size);
extern void InitBufTable(int size);
extern int BufTableLookup(BufferTag *tagPtr);
extern void BufTableInsert(BufferTag *tagPtr, int buf_id);
extern void BufTableDelete(BufferTag *tagPtr);
/* localbuf.c */
extern BufferDesc *LocalBufferAlloc(Relation reln, BlockNumber blockNum,
bool *foundPtr);
extern void WriteLocalBuffer(Buffer buffer, bool release);
extern void AtEOXact_LocalBuffers(bool isCommit);
#endif /* BUFMGR_INTERNALS_H */
|
