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/*-------------------------------------------------------------------------
*
* smgr.h
* storage manager switch public interface declarations.
*
*
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/storage/smgr.h,v 1.53 2005/10/15 02:49:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef SMGR_H
#define SMGR_H
#include "access/xlog.h"
#include "fmgr.h"
#include "storage/block.h"
#include "storage/relfilenode.h"
/*
* smgr.c maintains a table of SMgrRelation objects, which are essentially
* cached file handles. An SMgrRelation is created (if not already present)
* by smgropen(), and destroyed by smgrclose(). Note that neither of these
* operations imply I/O, they just create or destroy a hashtable entry.
* (But smgrclose() may release associated resources, such as OS-level file
* descriptors.)
*
* An SMgrRelation may have an "owner", which is just a pointer to it from
* somewhere else; smgr.c will clear this pointer if the SMgrRelation is
* closed. We use this to avoid dangling pointers from relcache to smgr
* without having to make the smgr explicitly aware of relcache. There
* can't be more than one "owner" pointer per SMgrRelation, but that's
* all we need.
*/
typedef struct SMgrRelationData
{
/* rnode is the hashtable lookup key, so it must be first! */
RelFileNode smgr_rnode; /* relation physical identifier */
/* pointer to owning pointer, or NULL if none */
struct SMgrRelationData **smgr_owner;
/* additional public fields may someday exist here */
/*
* Fields below here are intended to be private to smgr.c and its
* submodules. Do not touch them from elsewhere.
*/
int smgr_which; /* storage manager selector */
struct _MdfdVec *md_fd; /* for md.c; NULL if not open */
} SMgrRelationData;
typedef SMgrRelationData *SMgrRelation;
extern void smgrinit(void);
extern SMgrRelation smgropen(RelFileNode rnode);
extern void smgrsetowner(SMgrRelation *owner, SMgrRelation reln);
extern void smgrclose(SMgrRelation reln);
extern void smgrcloseall(void);
extern void smgrclosenode(RelFileNode rnode);
extern void smgrcreate(SMgrRelation reln, bool isTemp, bool isRedo);
extern void smgrscheduleunlink(SMgrRelation reln, bool isTemp);
extern void smgrdounlink(SMgrRelation reln, bool isTemp, bool isRedo);
extern void smgrextend(SMgrRelation reln, BlockNumber blocknum, char *buffer,
bool isTemp);
extern void smgrread(SMgrRelation reln, BlockNumber blocknum, char *buffer);
extern void smgrwrite(SMgrRelation reln, BlockNumber blocknum, char *buffer,
bool isTemp);
extern BlockNumber smgrnblocks(SMgrRelation reln);
extern BlockNumber smgrtruncate(SMgrRelation reln, BlockNumber nblocks,
bool isTemp);
extern void smgrimmedsync(SMgrRelation reln);
extern void smgrDoPendingDeletes(bool isCommit);
extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr);
extern void AtSubCommit_smgr(void);
extern void AtSubAbort_smgr(void);
extern void PostPrepare_smgr(void);
extern void smgrcommit(void);
extern void smgrabort(void);
extern void smgrsync(void);
extern void smgr_redo(XLogRecPtr lsn, XLogRecord *record);
extern void smgr_desc(char *buf, uint8 xl_info, char *rec);
/* internals: move me elsewhere -- ay 7/94 */
/* in md.c */
extern bool mdinit(void);
extern bool mdclose(SMgrRelation reln);
extern bool mdcreate(SMgrRelation reln, bool isRedo);
extern bool mdunlink(RelFileNode rnode, bool isRedo);
extern bool mdextend(SMgrRelation reln, BlockNumber blocknum, char *buffer,
bool isTemp);
extern bool mdread(SMgrRelation reln, BlockNumber blocknum, char *buffer);
extern bool mdwrite(SMgrRelation reln, BlockNumber blocknum, char *buffer,
bool isTemp);
extern BlockNumber mdnblocks(SMgrRelation reln);
extern BlockNumber mdtruncate(SMgrRelation reln, BlockNumber nblocks,
bool isTemp);
extern bool mdimmedsync(SMgrRelation reln);
extern bool mdsync(void);
extern void RememberFsyncRequest(RelFileNode rnode, BlockNumber segno);
/* smgrtype.c */
extern Datum smgrout(PG_FUNCTION_ARGS);
extern Datum smgrin(PG_FUNCTION_ARGS);
extern Datum smgreq(PG_FUNCTION_ARGS);
extern Datum smgrne(PG_FUNCTION_ARGS);
#endif /* SMGR_H */
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