trAvis - MANAGER

Edit File: smgr.h

/*------------------------------------------------------------------------- * * 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 */