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/*-------------------------------------------------------------------------
*
* genam.h
* POSTGRES generalized index 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/genam.h
*
*-------------------------------------------------------------------------
*/
#ifndef GENAM_H
#define GENAM_H
#include "access/sdir.h"
#include "access/skey.h"
#include "nodes/tidbitmap.h"
#include "storage/lockdefs.h"
#include "utils/relcache.h"
#include "utils/snapshot.h"
/*
* Struct for statistics returned by ambuild
*/
typedef struct IndexBuildResult
{
double heap_tuples; /* # of tuples seen in parent table */
double index_tuples; /* # of tuples inserted into index */
} IndexBuildResult;
/*
* Struct for input arguments passed to ambulkdelete and amvacuumcleanup
*
* num_heap_tuples is accurate only when estimated_count is false;
* otherwise it's just an estimate (currently, the estimate is the
* prior value of the relation's pg_class.reltuples field). It will
* always just be an estimate during ambulkdelete.
*/
typedef struct IndexVacuumInfo
{
Relation index; /* the index being vacuumed */
bool analyze_only; /* ANALYZE (without any actual vacuum) */
bool estimated_count; /* num_heap_tuples is an estimate */
int message_level; /* ereport level for progress messages */
double num_heap_tuples; /* tuples remaining in heap */
BufferAccessStrategy strategy; /* access strategy for reads */
} IndexVacuumInfo;
/*
* Struct for statistics returned by ambulkdelete and amvacuumcleanup
*
* This struct is normally allocated by the first ambulkdelete call and then
* passed along through subsequent ones until amvacuumcleanup; however,
* amvacuumcleanup must be prepared to allocate it in the case where no
* ambulkdelete calls were made (because no tuples needed deletion).
* Note that an index AM could choose to return a larger struct
* of which this is just the first field; this provides a way for ambulkdelete
* to communicate additional private data to amvacuumcleanup.
*
* Note: pages_removed is the amount by which the index physically shrank,
* if any (ie the change in its total size on disk). pages_deleted and
* pages_free refer to free space within the index file. Some index AMs
* may compute num_index_tuples by reference to num_heap_tuples, in which
* case they should copy the estimated_count field from IndexVacuumInfo.
*/
typedef struct IndexBulkDeleteResult
{
BlockNumber num_pages; /* pages remaining in index */
BlockNumber pages_removed; /* # removed during vacuum operation */
bool estimated_count; /* num_index_tuples is an estimate */
double num_index_tuples; /* tuples remaining */
double tuples_removed; /* # removed during vacuum operation */
BlockNumber pages_deleted; /* # unused pages in index */
BlockNumber pages_free; /* # pages available for reuse */
} IndexBulkDeleteResult;
/* Typedef for callback function to determine if a tuple is bulk-deletable */
typedef bool (*IndexBulkDeleteCallback) (ItemPointer itemptr, void *state);
/* struct definitions appear in relscan.h */
typedef struct IndexScanDescData *IndexScanDesc;
typedef struct SysScanDescData *SysScanDesc;
/*
* Enumeration specifying the type of uniqueness check to perform in
* index_insert().
*
* UNIQUE_CHECK_YES is the traditional Postgres immediate check, possibly
* blocking to see if a conflicting transaction commits.
*
* For deferrable unique constraints, UNIQUE_CHECK_PARTIAL is specified at
* insertion time. The index AM should test if the tuple is unique, but
* should not throw error, block, or prevent the insertion if the tuple
* appears not to be unique. We'll recheck later when it is time for the
* constraint to be enforced. The AM must return true if the tuple is
* known unique, false if it is possibly non-unique. In the "true" case
* it is safe to omit the later recheck.
*
* When it is time to recheck the deferred constraint, a pseudo-insertion
* call is made with UNIQUE_CHECK_EXISTING. The tuple is already in the
* index in this case, so it should not be inserted again. Rather, just
* check for conflicting live tuples (possibly blocking).
*/
typedef enum IndexUniqueCheck
{
UNIQUE_CHECK_NO, /* Don't do any uniqueness checking */
UNIQUE_CHECK_YES, /* Enforce uniqueness at insertion time */
UNIQUE_CHECK_PARTIAL, /* Test uniqueness, but no error */
UNIQUE_CHECK_EXISTING /* Check if existing tuple is unique */
} IndexUniqueCheck;
/* Nullable "ORDER BY col op const" distance */
typedef struct IndexOrderByDistance
{
double value;
bool isnull;
} IndexOrderByDistance;
/*
* generalized index_ interface routines (in indexam.c)
*/
/*
* IndexScanIsValid
* True iff the index scan is valid.
*/
#define IndexScanIsValid(scan) PointerIsValid(scan)
extern Relation index_open(Oid relationId, LOCKMODE lockmode);
extern void index_close(Relation relation, LOCKMODE lockmode);
extern bool index_insert(Relation indexRelation,
Datum *values, bool *isnull,
ItemPointer heap_t_ctid,
Relation heapRelation,
IndexUniqueCheck checkUnique);
extern IndexScanDesc index_beginscan(Relation heapRelation,
Relation indexRelation,
Snapshot snapshot,
int nkeys, int norderbys);
extern IndexScanDesc index_beginscan_bitmap(Relation indexRelation,
Snapshot snapshot,
int nkeys);
extern void index_rescan(IndexScanDesc scan,
ScanKey keys, int nkeys,
ScanKey orderbys, int norderbys);
extern void index_endscan(IndexScanDesc scan);
extern void index_markpos(IndexScanDesc scan);
extern void index_restrpos(IndexScanDesc scan);
extern ItemPointer index_getnext_tid(IndexScanDesc scan,
ScanDirection direction);
extern HeapTuple index_fetch_heap(IndexScanDesc scan);
extern HeapTuple index_getnext(IndexScanDesc scan, ScanDirection direction);
extern int64 index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap);
extern IndexBulkDeleteResult *index_bulk_delete(IndexVacuumInfo *info,
IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback,
void *callback_state);
extern IndexBulkDeleteResult *index_vacuum_cleanup(IndexVacuumInfo *info,
IndexBulkDeleteResult *stats);
extern bool index_can_return(Relation indexRelation, int attno);
extern RegProcedure index_getprocid(Relation irel, AttrNumber attnum,
uint16 procnum);
extern FmgrInfo *index_getprocinfo(Relation irel, AttrNumber attnum,
uint16 procnum);
/*
* index access method support routines (in genam.c)
*/
extern IndexScanDesc RelationGetIndexScan(Relation indexRelation,
int nkeys, int norderbys);
extern void IndexScanEnd(IndexScanDesc scan);
extern char *BuildIndexValueDescription(Relation indexRelation,
Datum *values, bool *isnull);
/*
* heap-or-index access to system catalogs (in genam.c)
*/
extern SysScanDesc systable_beginscan(Relation heapRelation,
Oid indexId,
bool indexOK,
Snapshot snapshot,
int nkeys, ScanKey key);
extern HeapTuple systable_getnext(SysScanDesc sysscan);
extern bool systable_recheck_tuple(SysScanDesc sysscan, HeapTuple tup);
extern void systable_endscan(SysScanDesc sysscan);
extern SysScanDesc systable_beginscan_ordered(Relation heapRelation,
Relation indexRelation,
Snapshot snapshot,
int nkeys, ScanKey key);
extern HeapTuple systable_getnext_ordered(SysScanDesc sysscan,
ScanDirection direction);
extern void systable_endscan_ordered(SysScanDesc sysscan);
#endif /* GENAM_H */
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