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/*-------------------------------------------------------------------------
*
* amapi.h
* API for Postgres index access methods.
*
* Copyright (c) 2015-2018, PostgreSQL Global Development Group
*
* src/include/access/amapi.h
*
*-------------------------------------------------------------------------
*/
#ifndef AMAPI_H
#define AMAPI_H
#include "access/genam.h"
/*
* We don't wish to include planner header files here, since most of an index
* AM's implementation isn't concerned with those data structures. To allow
* declaring amcostestimate_function here, use forward struct references.
*/
struct PlannerInfo;
struct IndexPath;
/* Likewise, this file shouldn't depend on execnodes.h. */
struct IndexInfo;
/*
* Properties for amproperty API. This list covers properties known to the
* core code, but an index AM can define its own properties, by matching the
* string property name.
*/
typedef enum IndexAMProperty
{
AMPROP_UNKNOWN = 0, /* anything not known to core code */
AMPROP_ASC, /* column properties */
AMPROP_DESC,
AMPROP_NULLS_FIRST,
AMPROP_NULLS_LAST,
AMPROP_ORDERABLE,
AMPROP_DISTANCE_ORDERABLE,
AMPROP_RETURNABLE,
AMPROP_SEARCH_ARRAY,
AMPROP_SEARCH_NULLS,
AMPROP_CLUSTERABLE, /* index properties */
AMPROP_INDEX_SCAN,
AMPROP_BITMAP_SCAN,
AMPROP_BACKWARD_SCAN,
AMPROP_CAN_ORDER, /* AM properties */
AMPROP_CAN_UNIQUE,
AMPROP_CAN_MULTI_COL,
AMPROP_CAN_EXCLUDE,
AMPROP_CAN_INCLUDE
} IndexAMProperty;
/*
* Callback function signatures --- see indexam.sgml for more info.
*/
/* build new index */
typedef IndexBuildResult *(*ambuild_function) (Relation heapRelation,
Relation indexRelation,
struct IndexInfo *indexInfo);
/* build empty index */
typedef void (*ambuildempty_function) (Relation indexRelation);
/* insert this tuple */
typedef bool (*aminsert_function) (Relation indexRelation,
Datum *values,
bool *isnull,
ItemPointer heap_tid,
Relation heapRelation,
IndexUniqueCheck checkUnique,
struct IndexInfo *indexInfo);
/* bulk delete */
typedef IndexBulkDeleteResult *(*ambulkdelete_function) (IndexVacuumInfo *info,
IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback,
void *callback_state);
/* post-VACUUM cleanup */
typedef IndexBulkDeleteResult *(*amvacuumcleanup_function) (IndexVacuumInfo *info,
IndexBulkDeleteResult *stats);
/* can indexscan return IndexTuples? */
typedef bool (*amcanreturn_function) (Relation indexRelation, int attno);
/* estimate cost of an indexscan */
typedef void (*amcostestimate_function) (struct PlannerInfo *root,
struct IndexPath *path,
double loop_count,
Cost *indexStartupCost,
Cost *indexTotalCost,
Selectivity *indexSelectivity,
double *indexCorrelation,
double *indexPages);
/* parse index reloptions */
typedef bytea *(*amoptions_function) (Datum reloptions,
bool validate);
/* report AM, index, or index column property */
typedef bool (*amproperty_function) (Oid index_oid, int attno,
IndexAMProperty prop, const char *propname,
bool *res, bool *isnull);
/* validate definition of an opclass for this AM */
typedef bool (*amvalidate_function) (Oid opclassoid);
/* prepare for index scan */
typedef IndexScanDesc (*ambeginscan_function) (Relation indexRelation,
int nkeys,
int norderbys);
/* (re)start index scan */
typedef void (*amrescan_function) (IndexScanDesc scan,
ScanKey keys,
int nkeys,
ScanKey orderbys,
int norderbys);
/* next valid tuple */
typedef bool (*amgettuple_function) (IndexScanDesc scan,
ScanDirection direction);
/* fetch all valid tuples */
typedef int64 (*amgetbitmap_function) (IndexScanDesc scan,
TIDBitmap *tbm);
/* end index scan */
typedef void (*amendscan_function) (IndexScanDesc scan);
/* mark current scan position */
typedef void (*ammarkpos_function) (IndexScanDesc scan);
/* restore marked scan position */
typedef void (*amrestrpos_function) (IndexScanDesc scan);
/*
* Callback function signatures - for parallel index scans.
*/
/* estimate size of parallel scan descriptor */
typedef Size (*amestimateparallelscan_function) (void);
/* prepare for parallel index scan */
typedef void (*aminitparallelscan_function) (void *target);
/* (re)start parallel index scan */
typedef void (*amparallelrescan_function) (IndexScanDesc scan);
/*
* API struct for an index AM. Note this must be stored in a single palloc'd
* chunk of memory.
*/
typedef struct IndexAmRoutine
{
NodeTag type;
/*
* Total number of strategies (operators) by which we can traverse/search
* this AM. Zero if AM does not have a fixed set of strategy assignments.
*/
uint16 amstrategies;
/* total number of support functions that this AM uses */
uint16 amsupport;
/* does AM support ORDER BY indexed column's value? */
bool amcanorder;
/* does AM support ORDER BY result of an operator on indexed column? */
bool amcanorderbyop;
/* does AM support backward scanning? */
bool amcanbackward;
/* does AM support UNIQUE indexes? */
bool amcanunique;
/* does AM support multi-column indexes? */
bool amcanmulticol;
/* does AM require scans to have a constraint on the first index column? */
bool amoptionalkey;
/* does AM handle ScalarArrayOpExpr quals? */
bool amsearcharray;
/* does AM handle IS NULL/IS NOT NULL quals? */
bool amsearchnulls;
/* can index storage data type differ from column data type? */
bool amstorage;
/* can an index of this type be clustered on? */
bool amclusterable;
/* does AM handle predicate locks? */
bool ampredlocks;
/* does AM support parallel scan? */
bool amcanparallel;
/* does AM support columns included with clause INCLUDE? */
bool amcaninclude;
/* type of data stored in index, or InvalidOid if variable */
Oid amkeytype;
/*
* If you add new properties to either the above or the below lists, then
* they should also (usually) be exposed via the property API (see
* IndexAMProperty at the top of the file, and utils/adt/amutils.c).
*/
/* interface functions */
ambuild_function ambuild;
ambuildempty_function ambuildempty;
aminsert_function aminsert;
ambulkdelete_function ambulkdelete;
amvacuumcleanup_function amvacuumcleanup;
amcanreturn_function amcanreturn; /* can be NULL */
amcostestimate_function amcostestimate;
amoptions_function amoptions;
amproperty_function amproperty; /* can be NULL */
amvalidate_function amvalidate;
ambeginscan_function ambeginscan;
amrescan_function amrescan;
amgettuple_function amgettuple; /* can be NULL */
amgetbitmap_function amgetbitmap; /* can be NULL */
amendscan_function amendscan;
ammarkpos_function ammarkpos; /* can be NULL */
amrestrpos_function amrestrpos; /* can be NULL */
/* interface functions to support parallel index scans */
amestimateparallelscan_function amestimateparallelscan; /* can be NULL */
aminitparallelscan_function aminitparallelscan; /* can be NULL */
amparallelrescan_function amparallelrescan; /* can be NULL */
} IndexAmRoutine;
/* Functions in access/index/amapi.c */
extern IndexAmRoutine *GetIndexAmRoutine(Oid amhandler);
extern IndexAmRoutine *GetIndexAmRoutineByAmId(Oid amoid, bool noerror);
#endif /* AMAPI_H */
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