heapam.h

Go to the documentation of this file.

/*-------------------------------------------------------------------------
 *
 * heapam.h
 *    POSTGRES heap access method definitions.
 *
 *
 * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/access/heapam.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef HEAPAM_H
#define HEAPAM_H

#include "access/sdir.h"
#include "access/skey.h"
#include "nodes/lockoptions.h"
#include "nodes/primnodes.h"
#include "storage/bufpage.h"
#include "storage/lock.h"
#include "utils/relcache.h"
#include "utils/snapshot.h"


/* "options" flag bits for heap_insert */
#define HEAP_INSERT_SKIP_WAL    0x0001
#define HEAP_INSERT_SKIP_FSM    0x0002
#define HEAP_INSERT_FROZEN      0x0004
#define HEAP_INSERT_SPECULATIVE 0x0008

typedef struct BulkInsertStateData *BulkInsertState;

/*
 * Possible lock modes for a tuple.
 */
typedef enum LockTupleMode
{
    /* SELECT FOR KEY SHARE */
    LockTupleKeyShare,
    /* SELECT FOR SHARE */
    LockTupleShare,
    /* SELECT FOR NO KEY UPDATE, and UPDATEs that don't modify key columns */
    LockTupleNoKeyExclusive,
    /* SELECT FOR UPDATE, UPDATEs that modify key columns, and DELETE */
    LockTupleExclusive
} LockTupleMode;

#define MaxLockTupleMode    LockTupleExclusive

/*
 * When heap_update, heap_delete, or heap_lock_tuple fail because the target
 * tuple is already outdated, they fill in this struct to provide information
 * to the caller about what happened.
 * ctid is the target's ctid link: it is the same as the target's TID if the
 * target was deleted, or the location of the replacement tuple if the target
 * was updated.
 * xmax is the outdating transaction's XID.  If the caller wants to visit the
 * replacement tuple, it must check that this matches before believing the
 * replacement is really a match.
 * cmax is the outdating command's CID, but only when the failure code is
 * HeapTupleSelfUpdated (i.e., something in the current transaction outdated
 * the tuple); otherwise cmax is zero.  (We make this restriction because
 * HeapTupleHeaderGetCmax doesn't work for tuples outdated in other
 * transactions.)
 */
typedef struct HeapUpdateFailureData
{
    ItemPointerData ctid;
    TransactionId xmax;
    CommandId   cmax;
} HeapUpdateFailureData;


/* ----------------
 *      function prototypes for heap access method
 *
 * heap_create, heap_create_with_catalog, and heap_drop_with_catalog
 * are declared in catalog/heap.h
 * ----------------
 */

/* in heap/heapam.c */
extern Relation relation_open(Oid relationId, LOCKMODE lockmode);
extern Relation try_relation_open(Oid relationId, LOCKMODE lockmode);
extern Relation relation_openrv(const RangeVar *relation, LOCKMODE lockmode);
extern Relation relation_openrv_extended(const RangeVar *relation,
                         LOCKMODE lockmode, bool missing_ok);
extern void relation_close(Relation relation, LOCKMODE lockmode);

extern Relation heap_open(Oid relationId, LOCKMODE lockmode);
extern Relation heap_openrv(const RangeVar *relation, LOCKMODE lockmode);
extern Relation heap_openrv_extended(const RangeVar *relation,
                     LOCKMODE lockmode, bool missing_ok);

#define heap_close(r,l)  relation_close(r,l)

/* struct definitions appear in relscan.h */
typedef struct HeapScanDescData *HeapScanDesc;
typedef struct ParallelHeapScanDescData *ParallelHeapScanDesc;

/*
 * HeapScanIsValid
 *      True iff the heap scan is valid.
 */
#define HeapScanIsValid(scan) PointerIsValid(scan)

extern HeapScanDesc heap_beginscan(Relation relation, Snapshot snapshot,
               int nkeys, ScanKey key);
extern HeapScanDesc heap_beginscan_catalog(Relation relation, int nkeys,
                       ScanKey key);
extern HeapScanDesc heap_beginscan_strat(Relation relation, Snapshot snapshot,
                     int nkeys, ScanKey key,
                     bool allow_strat, bool allow_sync);
extern HeapScanDesc heap_beginscan_bm(Relation relation, Snapshot snapshot,
                  int nkeys, ScanKey key);
extern HeapScanDesc heap_beginscan_sampling(Relation relation,
                        Snapshot snapshot, int nkeys, ScanKey key,
                     bool allow_strat, bool allow_sync, bool allow_pagemode);
extern void heap_setscanlimits(HeapScanDesc scan, BlockNumber startBlk,
                   BlockNumber endBlk);
extern void heapgetpage(HeapScanDesc scan, BlockNumber page);
extern void heap_rescan(HeapScanDesc scan, ScanKey key);
extern void heap_rescan_set_params(HeapScanDesc scan, ScanKey key,
                     bool allow_strat, bool allow_sync, bool allow_pagemode);
extern void heap_endscan(HeapScanDesc scan);
extern HeapTuple heap_getnext(HeapScanDesc scan, ScanDirection direction);

extern Size heap_parallelscan_estimate(Snapshot snapshot);
extern void heap_parallelscan_initialize(ParallelHeapScanDesc target,
                             Relation relation, Snapshot snapshot);
extern HeapScanDesc heap_beginscan_parallel(Relation, ParallelHeapScanDesc);

extern bool heap_fetch(Relation relation, Snapshot snapshot,
           HeapTuple tuple, Buffer *userbuf, bool keep_buf,
           Relation stats_relation);
extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
                       Buffer buffer, Snapshot snapshot, HeapTuple heapTuple,
                       bool *all_dead, bool first_call);
extern bool heap_hot_search(ItemPointer tid, Relation relation,
                Snapshot snapshot, bool *all_dead);

extern void heap_get_latest_tid(Relation relation, Snapshot snapshot,
                    ItemPointer tid);
extern void setLastTid(const ItemPointer tid);

extern BulkInsertState GetBulkInsertState(void);
extern void FreeBulkInsertState(BulkInsertState);

extern Oid heap_insert(Relation relation, HeapTuple tup, CommandId cid,
            int options, BulkInsertState bistate);
extern void heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,
                  CommandId cid, int options, BulkInsertState bistate);
extern HTSU_Result heap_delete(Relation relation, ItemPointer tid,
            CommandId cid, Snapshot crosscheck, bool wait,
            HeapUpdateFailureData *hufd);
extern void heap_finish_speculative(Relation relation, HeapTuple tuple);
extern void heap_abort_speculative(Relation relation, HeapTuple tuple);
extern HTSU_Result heap_update(Relation relation, ItemPointer otid,
            HeapTuple newtup,
            CommandId cid, Snapshot crosscheck, bool wait,
            HeapUpdateFailureData *hufd, LockTupleMode *lockmode);
extern HTSU_Result heap_lock_tuple(Relation relation, HeapTuple tuple,
                CommandId cid, LockTupleMode mode, LockWaitPolicy wait_policy,
                bool follow_update,
                Buffer *buffer, HeapUpdateFailureData *hufd);
extern void heap_inplace_update(Relation relation, HeapTuple tuple);
extern bool heap_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
                  TransactionId cutoff_multi);
extern bool heap_tuple_needs_freeze(HeapTupleHeader tuple, TransactionId cutoff_xid,
                        MultiXactId cutoff_multi, Buffer buf);
extern bool heap_tuple_needs_eventual_freeze(HeapTupleHeader tuple);

extern Oid  simple_heap_insert(Relation relation, HeapTuple tup);
extern void simple_heap_delete(Relation relation, ItemPointer tid);
extern void simple_heap_update(Relation relation, ItemPointer otid,
                   HeapTuple tup);

extern void heap_sync(Relation relation);

/* in heap/pruneheap.c */
extern void heap_page_prune_opt(Relation relation, Buffer buffer);
extern int heap_page_prune(Relation relation, Buffer buffer,
                TransactionId OldestXmin,
                bool report_stats, TransactionId *latestRemovedXid);
extern void heap_page_prune_execute(Buffer buffer,
                        OffsetNumber *redirected, int nredirected,
                        OffsetNumber *nowdead, int ndead,
                        OffsetNumber *nowunused, int nunused);
extern void heap_get_root_tuples(Page page, OffsetNumber *root_offsets);

/* in heap/syncscan.c */
extern void ss_report_location(Relation rel, BlockNumber location);
extern BlockNumber ss_get_location(Relation rel, BlockNumber relnblocks);
extern void SyncScanShmemInit(void);
extern Size SyncScanShmemSize(void);

#endif   /* HEAPAM_H */