Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * smgr.h
4 : * storage manager switch public interface declarations.
5 : *
6 : *
7 : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
8 : * Portions Copyright (c) 1994, Regents of the University of California
9 : *
10 : * src/include/storage/smgr.h
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 : #ifndef SMGR_H
15 : #define SMGR_H
16 :
17 : #include "lib/ilist.h"
18 : #include "storage/aio_types.h"
19 : #include "storage/block.h"
20 : #include "storage/relfilelocator.h"
21 :
22 : /*
23 : * smgr.c maintains a table of SMgrRelation objects, which are essentially
24 : * cached file handles. An SMgrRelation is created (if not already present)
25 : * by smgropen(), and destroyed by smgrdestroy(). Note that neither of these
26 : * operations imply I/O, they just create or destroy a hashtable entry. (But
27 : * smgrdestroy() may release associated resources, such as OS-level file
28 : * descriptors.)
29 : *
30 : * An SMgrRelation may be "pinned", to prevent it from being destroyed while
31 : * it's in use. We use this to prevent pointers in relcache to smgr from being
32 : * invalidated. SMgrRelations that are not pinned are deleted at end of
33 : * transaction.
34 : */
35 : typedef struct SMgrRelationData
36 : {
37 : /* rlocator is the hashtable lookup key, so it must be first! */
38 : RelFileLocatorBackend smgr_rlocator; /* relation physical identifier */
39 :
40 : /*
41 : * The following fields are reset to InvalidBlockNumber upon a cache flush
42 : * event, and hold the last known size for each fork. This information is
43 : * currently only reliable during recovery, since there is no cache
44 : * invalidation for fork extension.
45 : */
46 : BlockNumber smgr_targblock; /* current insertion target block */
47 : BlockNumber smgr_cached_nblocks[MAX_FORKNUM + 1]; /* last known size */
48 :
49 : /* additional public fields may someday exist here */
50 :
51 : /*
52 : * Fields below here are intended to be private to smgr.c and its
53 : * submodules. Do not touch them from elsewhere.
54 : */
55 : int smgr_which; /* storage manager selector */
56 :
57 : /*
58 : * for md.c; per-fork arrays of the number of open segments
59 : * (md_num_open_segs) and the segments themselves (md_seg_fds).
60 : */
61 : int md_num_open_segs[MAX_FORKNUM + 1];
62 : struct _MdfdVec *md_seg_fds[MAX_FORKNUM + 1];
63 :
64 : /*
65 : * Pinning support. If unpinned (ie. pincount == 0), 'node' is a list
66 : * link in list of all unpinned SMgrRelations.
67 : */
68 : int pincount;
69 : dlist_node node;
70 : } SMgrRelationData;
71 :
72 : typedef SMgrRelationData *SMgrRelation;
73 :
74 : #define SmgrIsTemp(smgr) \
75 : RelFileLocatorBackendIsTemp((smgr)->smgr_rlocator)
76 :
77 : extern PGDLLIMPORT const PgAioTargetInfo aio_smgr_target_info;
78 :
79 : extern void smgrinit(void);
80 : extern SMgrRelation smgropen(RelFileLocator rlocator, ProcNumber backend);
81 : extern bool smgrexists(SMgrRelation reln, ForkNumber forknum);
82 : extern void smgrpin(SMgrRelation reln);
83 : extern void smgrunpin(SMgrRelation reln);
84 : extern void smgrclose(SMgrRelation reln);
85 : extern void smgrdestroyall(void);
86 : extern void smgrrelease(SMgrRelation reln);
87 : extern void smgrreleaseall(void);
88 : extern void smgrreleaserellocator(RelFileLocatorBackend rlocator);
89 : extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
90 : extern void smgrdosyncall(SMgrRelation *rels, int nrels);
91 : extern void smgrdounlinkall(SMgrRelation *rels, int nrels, bool isRedo);
92 : extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
93 : BlockNumber blocknum, const void *buffer, bool skipFsync);
94 : extern void smgrzeroextend(SMgrRelation reln, ForkNumber forknum,
95 : BlockNumber blocknum, int nblocks, bool skipFsync);
96 : extern bool smgrprefetch(SMgrRelation reln, ForkNumber forknum,
97 : BlockNumber blocknum, int nblocks);
98 : extern uint32 smgrmaxcombine(SMgrRelation reln, ForkNumber forknum,
99 : BlockNumber blocknum);
100 : extern void smgrreadv(SMgrRelation reln, ForkNumber forknum,
101 : BlockNumber blocknum,
102 : void **buffers, BlockNumber nblocks);
103 : extern void smgrstartreadv(PgAioHandle *ioh,
104 : SMgrRelation reln, ForkNumber forknum,
105 : BlockNumber blocknum,
106 : void **buffers, BlockNumber nblocks);
107 : extern void smgrwritev(SMgrRelation reln, ForkNumber forknum,
108 : BlockNumber blocknum,
109 : const void **buffers, BlockNumber nblocks,
110 : bool skipFsync);
111 : extern void smgrwriteback(SMgrRelation reln, ForkNumber forknum,
112 : BlockNumber blocknum, BlockNumber nblocks);
113 : extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);
114 : extern BlockNumber smgrnblocks_cached(SMgrRelation reln, ForkNumber forknum);
115 : extern void smgrtruncate(SMgrRelation reln, ForkNumber *forknum, int nforks,
116 : BlockNumber *old_nblocks,
117 : BlockNumber *nblocks);
118 : extern void smgrimmedsync(SMgrRelation reln, ForkNumber forknum);
119 : extern void smgrregistersync(SMgrRelation reln, ForkNumber forknum);
120 : extern void AtEOXact_SMgr(void);
121 : extern bool ProcessBarrierSmgrRelease(void);
122 :
123 : static inline void
124 177 : smgrread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
125 : void *buffer)
126 : {
127 177 : smgrreadv(reln, forknum, blocknum, &buffer, 1);
128 177 : }
129 :
130 : static inline void
131 8001 : smgrwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
132 : const void *buffer, bool skipFsync)
133 : {
134 8001 : smgrwritev(reln, forknum, blocknum, &buffer, 1, skipFsync);
135 8001 : }
136 :
137 : extern void pgaio_io_set_target_smgr(PgAioHandle *ioh,
138 : SMgrRelationData *smgr,
139 : ForkNumber forknum,
140 : BlockNumber blocknum,
141 : int nblocks,
142 : bool skip_fsync);
143 :
144 : #endif /* SMGR_H */
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