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postgresql/src/include/access/heapam.h

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/*-------------------------------------------------------------------------
*
* heapam.h
* POSTGRES heap access method definitions.
*
*
* Portions Copyright (c) 1996-2023, 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/relation.h" /* for backward compatibility */
#include "access/relscan.h"
#include "access/sdir.h"
#include "access/skey.h"
#include "access/table.h" /* for backward compatibility */
#include "access/tableam.h"
#include "nodes/lockoptions.h"
#include "nodes/primnodes.h"
#include "storage/bufpage.h"
#include "storage/dsm.h"
#include "storage/lockdefs.h"
#include "storage/shm_toc.h"
#include "utils/relcache.h"
#include "utils/snapshot.h"
/* "options" flag bits for heap_insert */
#define HEAP_INSERT_SKIP_FSM TABLE_INSERT_SKIP_FSM
#define HEAP_INSERT_FROZEN TABLE_INSERT_FROZEN
#define HEAP_INSERT_NO_LOGICAL TABLE_INSERT_NO_LOGICAL
#define HEAP_INSERT_SPECULATIVE 0x0010
typedef struct BulkInsertStateData *BulkInsertState;
struct TupleTableSlot;
struct VacuumCutoffs;
#define MaxLockTupleMode LockTupleExclusive
/*
* Descriptor for heap table scans.
*/
typedef struct HeapScanDescData
{
TableScanDescData rs_base; /* AM independent part of the descriptor */
/* state set up at initscan time */
BlockNumber rs_nblocks; /* total number of blocks in rel */
BlockNumber rs_startblock; /* block # to start at */
BlockNumber rs_numblocks; /* max number of blocks to scan */
/* rs_numblocks is usually InvalidBlockNumber, meaning "scan whole rel" */
/* scan current state */
bool rs_inited; /* false = scan not init'd yet */
OffsetNumber rs_coffset; /* current offset # in non-page-at-a-time mode */
BlockNumber rs_cblock; /* current block # in scan, if any */
Buffer rs_cbuf; /* current buffer in scan, if any */
/* NB: if rs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
BufferAccessStrategy rs_strategy; /* access strategy for reads */
HeapTupleData rs_ctup; /* current tuple in scan, if any */
/*
* For parallel scans to store page allocation data. NULL when not
* performing a parallel scan.
*/
ParallelBlockTableScanWorkerData *rs_parallelworkerdata;
/* these fields only used in page-at-a-time mode and for bitmap scans */
int rs_cindex; /* current tuple's index in vistuples */
int rs_ntuples; /* number of visible tuples on page */
OffsetNumber rs_vistuples[MaxHeapTuplesPerPage]; /* their offsets */
} HeapScanDescData;
typedef struct HeapScanDescData *HeapScanDesc;
/*
* Descriptor for fetches from heap via an index.
*/
typedef struct IndexFetchHeapData
{
IndexFetchTableData xs_base; /* AM independent part of the descriptor */
Buffer xs_cbuf; /* current heap buffer in scan, if any */
/* NB: if xs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
} IndexFetchHeapData;
/* Result codes for HeapTupleSatisfiesVacuum */
typedef enum
{
HEAPTUPLE_DEAD, /* tuple is dead and deletable */
HEAPTUPLE_LIVE, /* tuple is live (committed, no deleter) */
HEAPTUPLE_RECENTLY_DEAD, /* tuple is dead, but not deletable yet */
HEAPTUPLE_INSERT_IN_PROGRESS, /* inserting xact is still in progress */
HEAPTUPLE_DELETE_IN_PROGRESS, /* deleting xact is still in progress */
} HTSV_Result;
/*
* heap_prepare_freeze_tuple may request that heap_freeze_execute_prepared
* check any tuple's to-be-frozen xmin and/or xmax status using pg_xact
*/
#define HEAP_FREEZE_CHECK_XMIN_COMMITTED 0x01
#define HEAP_FREEZE_CHECK_XMAX_ABORTED 0x02
/* heap_prepare_freeze_tuple state describing how to freeze a tuple */
typedef struct HeapTupleFreeze
{
/* Fields describing how to process tuple */
TransactionId xmax;
uint16 t_infomask2;
uint16 t_infomask;
uint8 frzflags;
/* xmin/xmax check flags */
uint8 checkflags;
/* Page offset number for tuple */
OffsetNumber offset;
} HeapTupleFreeze;
/*
* State used by VACUUM to track the details of freezing all eligible tuples
* on a given heap page.
*
* VACUUM prepares freeze plans for each page via heap_prepare_freeze_tuple
* calls (every tuple with storage gets its own call). This page-level freeze
* state is updated across each call, which ultimately determines whether or
* not freezing the page is required.
*
* Aside from the basic question of whether or not freezing will go ahead, the
* state also tracks the oldest extant XID/MXID in the table as a whole, for
* the purposes of advancing relfrozenxid/relminmxid values in pg_class later
* on. Each heap_prepare_freeze_tuple call pushes NewRelfrozenXid and/or
* NewRelminMxid back as required to avoid unsafe final pg_class values. Any
* and all unfrozen XIDs or MXIDs that remain after VACUUM finishes _must_
* have values >= the final relfrozenxid/relminmxid values in pg_class. This
* includes XIDs that remain as MultiXact members from any tuple's xmax.
*
* When 'freeze_required' flag isn't set after all tuples are examined, the
* final choice on freezing is made by vacuumlazy.c. It can decide to trigger
* freezing based on whatever criteria it deems appropriate. However, it is
* recommended that vacuumlazy.c avoid early freezing when freezing does not
* enable setting the target page all-frozen in the visibility map afterwards.
*/
typedef struct HeapPageFreeze
{
/* Is heap_prepare_freeze_tuple caller required to freeze page? */
bool freeze_required;
/*
* "Freeze" NewRelfrozenXid/NewRelminMxid trackers.
*
* Trackers used when heap_freeze_execute_prepared freezes, or when there
* are zero freeze plans for a page. It is always valid for vacuumlazy.c
* to freeze any page, by definition. This even includes pages that have
* no tuples with storage to consider in the first place. That way the
* 'totally_frozen' results from heap_prepare_freeze_tuple can always be
* used in the same way, even when no freeze plans need to be executed to
* "freeze the page". Only the "freeze" path needs to consider the need
* to set pages all-frozen in the visibility map under this scheme.
*
* When we freeze a page, we generally freeze all XIDs < OldestXmin, only
* leaving behind XIDs that are ineligible for freezing, if any. And so
* you might wonder why these trackers are necessary at all; why should
* _any_ page that VACUUM freezes _ever_ be left with XIDs/MXIDs that
* ratchet back the top-level NewRelfrozenXid/NewRelminMxid trackers?
*
* It is useful to use a definition of "freeze the page" that does not
* overspecify how MultiXacts are affected. heap_prepare_freeze_tuple
* generally prefers to remove Multis eagerly, but lazy processing is used
* in cases where laziness allows VACUUM to avoid allocating a new Multi.
* The "freeze the page" trackers enable this flexibility.
*/
TransactionId FreezePageRelfrozenXid;
MultiXactId FreezePageRelminMxid;
/*
* "No freeze" NewRelfrozenXid/NewRelminMxid trackers.
*
* These trackers are maintained in the same way as the trackers used when
* VACUUM scans a page that isn't cleanup locked. Both code paths are
* based on the same general idea (do less work for this page during the
* ongoing VACUUM, at the cost of having to accept older final values).
*/
TransactionId NoFreezePageRelfrozenXid;
MultiXactId NoFreezePageRelminMxid;
} HeapPageFreeze;
/*
* Per-page state returned from pruning
*/
typedef struct PruneResult
{
int ndeleted; /* Number of tuples deleted from the page */
int nnewlpdead; /* Number of newly LP_DEAD items */
/*
* Tuple visibility is only computed once for each tuple, for correctness
* and efficiency reasons; see comment in heap_page_prune() for details.
* This is of type int8[], instead of HTSV_Result[], so we can use -1 to
* indicate no visibility has been computed, e.g. for LP_DEAD items.
*
* This needs to be MaxHeapTuplesPerPage + 1 long as FirstOffsetNumber is
* 1. Otherwise every access would need to subtract 1.
*/
int8 htsv[MaxHeapTuplesPerPage + 1];
} PruneResult;
/*
* Pruning calculates tuple visibility once and saves the results in an array
* of int8. See PruneResult.htsv for details. This helper function is meant to
* guard against examining visibility status array members which have not yet
* been computed.
*/
static inline HTSV_Result
htsv_get_valid_status(int status)
{
Assert(status >= HEAPTUPLE_DEAD &&
status <= HEAPTUPLE_DELETE_IN_PROGRESS);
return (HTSV_Result) status;
}
/* ----------------
* function prototypes for heap access method
*
* heap_create, heap_create_with_catalog, and heap_drop_with_catalog
* are declared in catalog/heap.h
* ----------------
*/
/*
* HeapScanIsValid
* True iff the heap scan is valid.
*/
#define HeapScanIsValid(scan) PointerIsValid(scan)
extern TableScanDesc heap_beginscan(Relation relation, Snapshot snapshot,
int nkeys, ScanKey key,
ParallelTableScanDesc parallel_scan,
uint32 flags);
extern void heap_setscanlimits(TableScanDesc sscan, BlockNumber startBlk,
BlockNumber numBlks);
extern void heapgetpage(TableScanDesc sscan, BlockNumber block);
extern void heap_rescan(TableScanDesc sscan, ScanKey key, bool set_params,
bool allow_strat, bool allow_sync, bool allow_pagemode);
extern void heap_endscan(TableScanDesc sscan);
extern HeapTuple heap_getnext(TableScanDesc sscan, ScanDirection direction);
extern bool heap_getnextslot(TableScanDesc sscan,
ScanDirection direction, struct TupleTableSlot *slot);
extern void heap_set_tidrange(TableScanDesc sscan, ItemPointer mintid,
ItemPointer maxtid);
extern bool heap_getnextslot_tidrange(TableScanDesc sscan,
ScanDirection direction,
TupleTableSlot *slot);
extern bool heap_fetch(Relation relation, Snapshot snapshot,
HeapTuple tuple, Buffer *userbuf, bool keep_buf);
extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
Buffer buffer, Snapshot snapshot, HeapTuple heapTuple,
bool *all_dead, bool first_call);
extern void heap_get_latest_tid(TableScanDesc sscan, ItemPointer tid);
extern BulkInsertState GetBulkInsertState(void);
extern void FreeBulkInsertState(BulkInsertState);
extern void ReleaseBulkInsertStatePin(BulkInsertState bistate);
extern void heap_insert(Relation relation, HeapTuple tup, CommandId cid,
int options, BulkInsertState bistate);
extern void heap_multi_insert(Relation relation, struct TupleTableSlot **slots,
int ntuples, CommandId cid, int options,
BulkInsertState bistate);
extern TM_Result heap_delete(Relation relation, ItemPointer tid,
CommandId cid, Snapshot crosscheck, bool wait,
struct TM_FailureData *tmfd, bool changingPart);
extern void heap_finish_speculative(Relation relation, ItemPointer tid);
extern void heap_abort_speculative(Relation relation, ItemPointer tid);
extern TM_Result heap_update(Relation relation, ItemPointer otid,
HeapTuple newtup,
CommandId cid, Snapshot crosscheck, bool wait,
struct TM_FailureData *tmfd, LockTupleMode *lockmode,
TU_UpdateIndexes *update_indexes);
extern TM_Result heap_lock_tuple(Relation relation, HeapTuple tuple,
CommandId cid, LockTupleMode mode, LockWaitPolicy wait_policy,
bool follow_updates,
Buffer *buffer, struct TM_FailureData *tmfd);
extern void heap_inplace_update(Relation relation, HeapTuple tuple);
extern bool heap_prepare_freeze_tuple(HeapTupleHeader tuple,
const struct VacuumCutoffs *cutoffs,
HeapPageFreeze *pagefrz,
HeapTupleFreeze *frz, bool *totally_frozen);
extern void heap_freeze_execute_prepared(Relation rel, Buffer buffer,
TransactionId snapshotConflictHorizon,
HeapTupleFreeze *tuples, int ntuples);
extern bool heap_freeze_tuple(HeapTupleHeader tuple,
TransactionId relfrozenxid, TransactionId relminmxid,
TransactionId FreezeLimit, TransactionId MultiXactCutoff);
extern bool heap_tuple_should_freeze(HeapTupleHeader tuple,
const struct VacuumCutoffs *cutoffs,
TransactionId *NoFreezePageRelfrozenXid,
MultiXactId *NoFreezePageRelminMxid);
extern bool heap_tuple_needs_eventual_freeze(HeapTupleHeader tuple);
extern void 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, TU_UpdateIndexes *update_indexes);
extern TransactionId heap_index_delete_tuples(Relation rel,
TM_IndexDeleteOp *delstate);
/* in heap/pruneheap.c */
struct GlobalVisState;
extern void heap_page_prune_opt(Relation relation, Buffer buffer);
extern void heap_page_prune(Relation relation, Buffer buffer,
struct GlobalVisState *vistest,
PruneResult *presult,
OffsetNumber *off_loc);
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/vacuumlazy.c */
struct VacuumParams;
extern void heap_vacuum_rel(Relation rel,
struct VacuumParams *params, BufferAccessStrategy bstrategy);
/* in heap/heapam_visibility.c */
extern bool HeapTupleSatisfiesVisibility(HeapTuple htup, Snapshot snapshot,
Buffer buffer);
extern TM_Result HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
Buffer buffer);
extern HTSV_Result HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
Buffer buffer);
extern HTSV_Result HeapTupleSatisfiesVacuumHorizon(HeapTuple htup, Buffer buffer,
TransactionId *dead_after);
extern void HeapTupleSetHintBits(HeapTupleHeader tuple, Buffer buffer,
uint16 infomask, TransactionId xid);
extern bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple);
extern bool HeapTupleIsSurelyDead(HeapTuple htup,
struct GlobalVisState *vistest);
/*
* To avoid leaking too much knowledge about reorderbuffer implementation
* details this is implemented in reorderbuffer.c not heapam_visibility.c
*/
struct HTAB;
extern bool ResolveCminCmaxDuringDecoding(struct HTAB *tuplecid_data,
Snapshot snapshot,
HeapTuple htup,
Buffer buffer,
CommandId *cmin, CommandId *cmax);
extern void HeapCheckForSerializableConflictOut(bool visible, Relation relation, HeapTuple tuple,
Buffer buffer, Snapshot snapshot);
#endif /* HEAPAM_H */
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