1 /*-------------------------------------------------------------------------
4 * storage manager switch public interface declarations.
7 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * $PostgreSQL: pgsql/src/include/storage/smgr.h,v 1.64 2008/11/19 10:34:52 heikki Exp $
12 *-------------------------------------------------------------------------
17 #include "access/xlog.h"
19 #include "storage/block.h"
20 #include "storage/relfilenode.h"
24 * smgr.c maintains a table of SMgrRelation objects, which are essentially
25 * cached file handles. An SMgrRelation is created (if not already present)
26 * by smgropen(), and destroyed by smgrclose(). Note that neither of these
27 * operations imply I/O, they just create or destroy a hashtable entry.
28 * (But smgrclose() may release associated resources, such as OS-level file
31 * An SMgrRelation may have an "owner", which is just a pointer to it from
32 * somewhere else; smgr.c will clear this pointer if the SMgrRelation is
33 * closed. We use this to avoid dangling pointers from relcache to smgr
34 * without having to make the smgr explicitly aware of relcache. There
35 * can't be more than one "owner" pointer per SMgrRelation, but that's
38 typedef struct SMgrRelationData
40 /* rnode is the hashtable lookup key, so it must be first! */
41 RelFileNode smgr_rnode; /* relation physical identifier */
43 /* pointer to owning pointer, or NULL if none */
44 struct SMgrRelationData **smgr_owner;
46 /* additional public fields may someday exist here */
49 * Fields below here are intended to be private to smgr.c and its
50 * submodules. Do not touch them from elsewhere.
52 int smgr_which; /* storage manager selector */
54 /* for md.c; NULL for forks that are not open */
55 struct _MdfdVec *md_fd[MAX_FORKNUM + 1];
58 typedef SMgrRelationData *SMgrRelation;
61 extern void smgrinit(void);
62 extern SMgrRelation smgropen(RelFileNode rnode);
63 extern bool smgrexists(SMgrRelation reln, ForkNumber forknum);
64 extern void smgrsetowner(SMgrRelation *owner, SMgrRelation reln);
65 extern void smgrclose(SMgrRelation reln);
66 extern void smgrcloseall(void);
67 extern void smgrclosenode(RelFileNode rnode);
68 extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
69 extern void smgrdounlink(SMgrRelation reln, ForkNumber forknum,
70 bool isTemp, bool isRedo);
71 extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
72 BlockNumber blocknum, char *buffer, bool isTemp);
73 extern void smgrread(SMgrRelation reln, ForkNumber forknum,
74 BlockNumber blocknum, char *buffer);
75 extern void smgrwrite(SMgrRelation reln, ForkNumber forknum,
76 BlockNumber blocknum, char *buffer, bool isTemp);
77 extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);
78 extern void smgrtruncate(SMgrRelation reln, ForkNumber forknum,
79 BlockNumber nblocks, bool isTemp);
80 extern void smgrimmedsync(SMgrRelation reln, ForkNumber forknum);
81 extern void smgrpreckpt(void);
82 extern void smgrsync(void);
83 extern void smgrpostckpt(void);
86 /* internals: move me elsewhere -- ay 7/94 */
89 extern void mdinit(void);
90 extern void mdclose(SMgrRelation reln, ForkNumber forknum);
91 extern void mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
92 extern bool mdexists(SMgrRelation reln, ForkNumber forknum);
93 extern void mdunlink(RelFileNode rnode, ForkNumber forknum, bool isRedo);
94 extern void mdextend(SMgrRelation reln, ForkNumber forknum,
95 BlockNumber blocknum, char *buffer, bool isTemp);
96 extern void mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
98 extern void mdwrite(SMgrRelation reln, ForkNumber forknum,
99 BlockNumber blocknum, char *buffer, bool isTemp);
100 extern BlockNumber mdnblocks(SMgrRelation reln, ForkNumber forknum);
101 extern void mdtruncate(SMgrRelation reln, ForkNumber forknum,
102 BlockNumber nblocks, bool isTemp);
103 extern void mdimmedsync(SMgrRelation reln, ForkNumber forknum);
104 extern void mdpreckpt(void);
105 extern void mdsync(void);
106 extern void mdpostckpt(void);
108 extern void RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum,
110 extern void ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum);
111 extern void ForgetDatabaseFsyncRequests(Oid dbid);
114 extern Datum smgrout(PG_FUNCTION_ARGS);
115 extern Datum smgrin(PG_FUNCTION_ARGS);
116 extern Datum smgreq(PG_FUNCTION_ARGS);
117 extern Datum smgrne(PG_FUNCTION_ARGS);