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GUC variable effective_io_concurrency controls how many concurrent block prefetch requests will be issued. (The best way to handle this for plain index scans is still under debate, so that part is not applied yet --- tgl) Greg Stark
123 lines
4.7 KiB
C
123 lines
4.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* smgr.h
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* storage manager switch public interface declarations.
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*
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*
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* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/storage/smgr.h,v 1.66 2009/01/12 05:10:45 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef SMGR_H
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#define SMGR_H
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#include "access/xlog.h"
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#include "fmgr.h"
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#include "storage/block.h"
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#include "storage/relfilenode.h"
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/*
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* smgr.c maintains a table of SMgrRelation objects, which are essentially
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* cached file handles. An SMgrRelation is created (if not already present)
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* by smgropen(), and destroyed by smgrclose(). Note that neither of these
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* operations imply I/O, they just create or destroy a hashtable entry.
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* (But smgrclose() may release associated resources, such as OS-level file
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* descriptors.)
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*
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* An SMgrRelation may have an "owner", which is just a pointer to it from
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* somewhere else; smgr.c will clear this pointer if the SMgrRelation is
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* closed. We use this to avoid dangling pointers from relcache to smgr
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* without having to make the smgr explicitly aware of relcache. There
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* can't be more than one "owner" pointer per SMgrRelation, but that's
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* all we need.
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*/
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typedef struct SMgrRelationData
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{
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/* rnode is the hashtable lookup key, so it must be first! */
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RelFileNode smgr_rnode; /* relation physical identifier */
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/* pointer to owning pointer, or NULL if none */
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struct SMgrRelationData **smgr_owner;
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/* additional public fields may someday exist here */
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/*
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* Fields below here are intended to be private to smgr.c and its
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* submodules. Do not touch them from elsewhere.
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*/
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int smgr_which; /* storage manager selector */
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/* for md.c; NULL for forks that are not open */
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struct _MdfdVec *md_fd[MAX_FORKNUM + 1];
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} SMgrRelationData;
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typedef SMgrRelationData *SMgrRelation;
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extern void smgrinit(void);
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extern SMgrRelation smgropen(RelFileNode rnode);
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extern bool smgrexists(SMgrRelation reln, ForkNumber forknum);
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extern void smgrsetowner(SMgrRelation *owner, SMgrRelation reln);
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extern void smgrclose(SMgrRelation reln);
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extern void smgrcloseall(void);
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extern void smgrclosenode(RelFileNode rnode);
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extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
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extern void smgrdounlink(SMgrRelation reln, ForkNumber forknum,
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bool isTemp, bool isRedo);
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extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
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BlockNumber blocknum, char *buffer, bool isTemp);
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extern void smgrprefetch(SMgrRelation reln, ForkNumber forknum,
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BlockNumber blocknum);
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extern void smgrread(SMgrRelation reln, ForkNumber forknum,
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BlockNumber blocknum, char *buffer);
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extern void smgrwrite(SMgrRelation reln, ForkNumber forknum,
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BlockNumber blocknum, char *buffer, bool isTemp);
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extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);
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extern void smgrtruncate(SMgrRelation reln, ForkNumber forknum,
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BlockNumber nblocks, bool isTemp);
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extern void smgrimmedsync(SMgrRelation reln, ForkNumber forknum);
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extern void smgrpreckpt(void);
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extern void smgrsync(void);
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extern void smgrpostckpt(void);
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/* internals: move me elsewhere -- ay 7/94 */
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/* in md.c */
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extern void mdinit(void);
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extern void mdclose(SMgrRelation reln, ForkNumber forknum);
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extern void mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
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extern bool mdexists(SMgrRelation reln, ForkNumber forknum);
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extern void mdunlink(RelFileNode rnode, ForkNumber forknum, bool isRedo);
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extern void mdextend(SMgrRelation reln, ForkNumber forknum,
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BlockNumber blocknum, char *buffer, bool isTemp);
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extern void mdprefetch(SMgrRelation reln, ForkNumber forknum,
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BlockNumber blocknum);
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extern void mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
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char *buffer);
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extern void mdwrite(SMgrRelation reln, ForkNumber forknum,
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BlockNumber blocknum, char *buffer, bool isTemp);
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extern BlockNumber mdnblocks(SMgrRelation reln, ForkNumber forknum);
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extern void mdtruncate(SMgrRelation reln, ForkNumber forknum,
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BlockNumber nblocks, bool isTemp);
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extern void mdimmedsync(SMgrRelation reln, ForkNumber forknum);
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extern void mdpreckpt(void);
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extern void mdsync(void);
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extern void mdpostckpt(void);
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extern void RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum,
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BlockNumber segno);
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extern void ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum);
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extern void ForgetDatabaseFsyncRequests(Oid dbid);
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/* smgrtype.c */
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extern Datum smgrout(PG_FUNCTION_ARGS);
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extern Datum smgrin(PG_FUNCTION_ARGS);
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extern Datum smgreq(PG_FUNCTION_ARGS);
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extern Datum smgrne(PG_FUNCTION_ARGS);
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#endif /* SMGR_H */
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