1 /*-------------------------------------------------------------------------
4 * storage manager switch public interface declarations.
7 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * $PostgreSQL: pgsql/src/include/storage/smgr.h,v 1.50 2005/01/10 20:02:23 tgl 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 struct _MdfdVec *md_fd; /* for md.c; NULL if not open */
57 typedef SMgrRelationData *SMgrRelation;
60 extern void smgrinit(void);
61 extern SMgrRelation smgropen(RelFileNode rnode);
62 extern void smgrsetowner(SMgrRelation *owner, SMgrRelation reln);
63 extern void smgrclose(SMgrRelation reln);
64 extern void smgrcloseall(void);
65 extern void smgrclosenode(RelFileNode rnode);
66 extern void smgrcreate(SMgrRelation reln, bool isTemp, bool isRedo);
67 extern void smgrscheduleunlink(SMgrRelation reln, bool isTemp);
68 extern void smgrdounlink(SMgrRelation reln, bool isTemp, bool isRedo);
69 extern void smgrextend(SMgrRelation reln, BlockNumber blocknum, char *buffer,
71 extern void smgrread(SMgrRelation reln, BlockNumber blocknum, char *buffer);
72 extern void smgrwrite(SMgrRelation reln, BlockNumber blocknum, char *buffer,
74 extern BlockNumber smgrnblocks(SMgrRelation reln);
75 extern BlockNumber smgrtruncate(SMgrRelation reln, BlockNumber nblocks,
77 extern void smgrimmedsync(SMgrRelation reln);
78 extern void smgrDoPendingDeletes(bool isCommit);
79 extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr);
80 extern void AtSubCommit_smgr(void);
81 extern void AtSubAbort_smgr(void);
82 extern void smgrcommit(void);
83 extern void smgrabort(void);
84 extern void smgrsync(void);
86 extern void smgr_redo(XLogRecPtr lsn, XLogRecord *record);
87 extern void smgr_undo(XLogRecPtr lsn, XLogRecord *record);
88 extern void smgr_desc(char *buf, uint8 xl_info, char *rec);
91 /* internals: move me elsewhere -- ay 7/94 */
94 extern bool mdinit(void);
95 extern bool mdclose(SMgrRelation reln);
96 extern bool mdcreate(SMgrRelation reln, bool isRedo);
97 extern bool mdunlink(RelFileNode rnode, bool isRedo);
98 extern bool mdextend(SMgrRelation reln, BlockNumber blocknum, char *buffer,
100 extern bool mdread(SMgrRelation reln, BlockNumber blocknum, char *buffer);
101 extern bool mdwrite(SMgrRelation reln, BlockNumber blocknum, char *buffer,
103 extern BlockNumber mdnblocks(SMgrRelation reln);
104 extern BlockNumber mdtruncate(SMgrRelation reln, BlockNumber nblocks,
106 extern bool mdimmedsync(SMgrRelation reln);
107 extern bool mdsync(void);
109 extern void RememberFsyncRequest(RelFileNode rnode, BlockNumber segno);
112 extern Datum smgrout(PG_FUNCTION_ARGS);
113 extern Datum smgrin(PG_FUNCTION_ARGS);
114 extern Datum smgreq(PG_FUNCTION_ARGS);
115 extern Datum smgrne(PG_FUNCTION_ARGS);