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/*-------------------------------------------------------------------------
*
* smgr.h
* storage manager switch public interface declarations.
*
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/storage/smgr.h
*
*-------------------------------------------------------------------------
*/
#ifndef SMGR_H
#define SMGR_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.
*
* SMgrRelations that do not have an "owner" are considered to be transient,
* and are deleted at end of transaction.
*/
typedef struct SMgrRelationData
{
/* rnode is the hashtable lookup key, so it must be first! */
RelFileNodeBackend smgr_rnode; /* relation physical identifier */
/* pointer to owning pointer, or NULL if none */
struct SMgrRelationData **smgr_owner;
/*
* These next three fields are not actually used or manipulated by smgr,
* except that they are reset to InvalidBlockNumber upon a cache flush
* event (in particular, upon truncation of the relation). Higher levels
* store cached state here so that it will be reset when truncation
* happens. In all three cases, InvalidBlockNumber means "unknown".
*/
BlockNumber smgr_targblock; /* current insertion target block */
BlockNumber smgr_fsm_nblocks; /* last known size of fsm fork */
BlockNumber smgr_vm_nblocks; /* last known size of vm fork */
/* 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 */
/* for md.c; NULL for forks that are not open */
struct _MdfdVec *md_fd[MAX_FORKNUM + 1];
/* if unowned, list link in list of all unowned SMgrRelations */
struct SMgrRelationData *next_unowned_reln;
} SMgrRelationData;
typedef SMgrRelationData *SMgrRelation;
#define SmgrIsTemp(smgr) \
RelFileNodeBackendIsTemp((smgr)->smgr_rnode)
extern void smgrinit(void);
extern SMgrRelation smgropen(RelFileNode rnode, BackendId backend);
extern bool smgrexists(SMgrRelation reln, ForkNumber forknum);
extern void smgrsetowner(SMgrRelation *owner, SMgrRelation reln);
extern void smgrclearowner(SMgrRelation *owner, SMgrRelation reln);
extern void smgrclose(SMgrRelation reln);
extern void smgrcloseall(void);
extern void smgrclosenode(RelFileNodeBackend rnode);
extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
extern void smgrdounlink(SMgrRelation reln, bool isRedo);
extern void smgrdounlinkfork(SMgrRelation reln, ForkNumber forknum, bool isRedo);
extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, char *buffer, bool skipFsync);
extern void smgrprefetch(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum);
extern void smgrread(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, char *buffer);
extern void smgrwrite(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, char *buffer, bool skipFsync);
extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);
extern void smgrtruncate(SMgrRelation reln, ForkNumber forknum,
BlockNumber nblocks);
extern void smgrimmedsync(SMgrRelation reln, ForkNumber forknum);
extern void smgrpreckpt(void);
extern void smgrsync(void);
extern void smgrpostckpt(void);
extern void AtEOXact_SMgr(void);
/* internals: move me elsewhere -- ay 7/94 */
/* in md.c */
extern void mdinit(void);
extern void mdclose(SMgrRelation reln, ForkNumber forknum);
extern void mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
extern bool mdexists(SMgrRelation reln, ForkNumber forknum);
extern void mdunlink(RelFileNodeBackend rnode, ForkNumber forknum, bool isRedo);
extern void mdextend(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, char *buffer, bool skipFsync);
extern void mdprefetch(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum);
extern void mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
char *buffer);
extern void mdwrite(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, char *buffer, bool skipFsync);
extern BlockNumber mdnblocks(SMgrRelation reln, ForkNumber forknum);
extern void mdtruncate(SMgrRelation reln, ForkNumber forknum,
BlockNumber nblocks);
extern void mdimmedsync(SMgrRelation reln, ForkNumber forknum);
extern void mdpreckpt(void);
extern void mdsync(void);
extern void mdpostckpt(void);
extern void SetForwardFsyncRequests(void);
extern void RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum,
BlockNumber segno);
extern void ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum);
extern void ForgetDatabaseFsyncRequests(Oid dbid);
/* 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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