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- /*-------------------------------------------------------------------------
- *
- * tuplesort.h
- * Generalized tuple sorting routines.
- *
- * This module handles sorting of heap tuples, index tuples, or single
- * Datums (and could easily support other kinds of sortable objects,
- * if necessary). It works efficiently for both small and large amounts
- * of data. Small amounts are sorted in-memory using qsort(). Large
- * amounts are sorted using temporary files and a standard external sort
- * algorithm.
- *
- * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * src/include/utils/tuplesort.h
- *
- *-------------------------------------------------------------------------
- */
- #ifndef TUPLESORT_H
- #define TUPLESORT_H
- #include "access/itup.h"
- #include "executor/tuptable.h"
- #include "fmgr.h"
- #include "utils/relcache.h"
- /* Tuplesortstate is an opaque type whose details are not known outside
- * tuplesort.c.
- */
- typedef struct Tuplesortstate Tuplesortstate;
- /*
- * We provide multiple interfaces to what is essentially the same code,
- * since different callers have different data to be sorted and want to
- * specify the sort key information differently. There are two APIs for
- * sorting HeapTuples and two more for sorting IndexTuples. Yet another
- * API supports sorting bare Datums.
- *
- * The "heap" API actually stores/sorts MinimalTuples, which means it doesn't
- * preserve the system columns (tuple identity and transaction visibility
- * info). The sort keys are specified by column numbers within the tuples
- * and sort operator OIDs. We save some cycles by passing and returning the
- * tuples in TupleTableSlots, rather than forming actual HeapTuples (which'd
- * have to be converted to MinimalTuples). This API works well for sorts
- * executed as parts of plan trees.
- *
- * The "cluster" API stores/sorts full HeapTuples including all visibility
- * info. The sort keys are specified by reference to a btree index that is
- * defined on the relation to be sorted. Note that putheaptuple/getheaptuple
- * go with this API, not the "begin_heap" one!
- *
- * The "index_btree" API stores/sorts IndexTuples (preserving all their
- * header fields). The sort keys are specified by a btree index definition.
- *
- * The "index_hash" API is similar to index_btree, but the tuples are
- * actually sorted by their hash codes not the raw data.
- */
- extern Tuplesortstate *tuplesort_begin_heap(TupleDesc tupDesc,
- int nkeys, AttrNumber *attNums,
- Oid *sortOperators, Oid *sortCollations,
- bool *nullsFirstFlags,
- int workMem, bool randomAccess);
- extern Tuplesortstate *tuplesort_begin_cluster(TupleDesc tupDesc,
- Relation indexRel,
- int workMem, bool randomAccess);
- extern Tuplesortstate *tuplesort_begin_index_btree(Relation heapRel,
- Relation indexRel,
- bool enforceUnique,
- int workMem, bool randomAccess);
- extern Tuplesortstate *tuplesort_begin_index_hash(Relation heapRel,
- Relation indexRel,
- uint32 hash_mask,
- int workMem, bool randomAccess);
- extern Tuplesortstate *tuplesort_begin_datum(Oid datumType,
- Oid sortOperator, Oid sortCollation,
- bool nullsFirstFlag,
- int workMem, bool randomAccess);
- extern void tuplesort_set_bound(Tuplesortstate *state, int64 bound);
- extern void tuplesort_puttupleslot(Tuplesortstate *state,
- TupleTableSlot *slot);
- extern void tuplesort_putheaptuple(Tuplesortstate *state, HeapTuple tup);
- extern void tuplesort_putindextuplevalues(Tuplesortstate *state,
- Relation rel, ItemPointer self,
- Datum *values, bool *isnull);
- extern void tuplesort_putdatum(Tuplesortstate *state, Datum val,
- bool isNull);
- extern void tuplesort_performsort(Tuplesortstate *state);
- extern bool tuplesort_gettupleslot(Tuplesortstate *state, bool forward,
- TupleTableSlot *slot, Datum *abbrev);
- extern HeapTuple tuplesort_getheaptuple(Tuplesortstate *state, bool forward,
- bool *should_free);
- extern IndexTuple tuplesort_getindextuple(Tuplesortstate *state, bool forward,
- bool *should_free);
- extern bool tuplesort_getdatum(Tuplesortstate *state, bool forward,
- Datum *val, bool *isNull, Datum *abbrev);
- extern bool tuplesort_skiptuples(Tuplesortstate *state, int64 ntuples,
- bool forward);
- extern void tuplesort_end(Tuplesortstate *state);
- extern void tuplesort_get_stats(Tuplesortstate *state,
- const char **sortMethod,
- const char **spaceType,
- long *spaceUsed);
- extern int tuplesort_merge_order(int64 allowedMem);
- /*
- * These routines may only be called if randomAccess was specified 'true'.
- * Likewise, backwards scan in gettuple/getdatum is only allowed if
- * randomAccess was specified.
- */
- extern void tuplesort_rescan(Tuplesortstate *state);
- extern void tuplesort_markpos(Tuplesortstate *state);
- extern void tuplesort_restorepos(Tuplesortstate *state);
- #endif /* TUPLESORT_H */
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