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69 lines
2.3 KiB
69 lines
2.3 KiB
26 years ago
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/*-------------------------------------------------------------------------
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*
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* tuplesort.h
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* Generalized tuple sorting routines.
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*
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* This module handles sorting of either heap tuples or index tuples
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* (and could fairly easily support other kinds of sortable objects,
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* if necessary). It works efficiently for both small and large amounts
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* of data. Small amounts are sorted in-memory using qsort(). Large
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* amounts are sorted using temporary files and a standard external sort
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* algorithm.
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: tuplesort.h,v 1.1 1999/10/17 22:15:09 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef TUPLESORT_H
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#define TUPLESORT_H
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#include "access/htup.h"
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#include "access/itup.h"
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#include "access/skey.h"
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#include "access/tupdesc.h"
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#include "utils/rel.h"
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/* Tuplesortstate is an opaque type whose details are not known outside tuplesort.c. */
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typedef struct Tuplesortstate Tuplesortstate;
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/*
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* We provide two different interfaces to what is essentially the same
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* code: one for sorting HeapTuples and one for sorting IndexTuples.
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* They differ primarily in the way that the sort key information is
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* supplied.
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*/
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extern Tuplesortstate *tuplesort_begin_heap(TupleDesc tupDesc,
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int nkeys, ScanKey keys,
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bool randomAccess);
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extern Tuplesortstate *tuplesort_begin_index(Relation indexRel,
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bool enforceUnique,
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bool randomAccess);
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extern void tuplesort_puttuple(Tuplesortstate *state, void *tuple);
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extern void tuplesort_performsort(Tuplesortstate *state);
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extern void *tuplesort_gettuple(Tuplesortstate *state, bool forward,
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bool *should_free);
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#define tuplesort_getheaptuple(state, forward, should_free) \
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((HeapTuple) tuplesort_gettuple(state, forward, should_free))
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#define tuplesort_getindextuple(state, forward, should_free) \
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((IndexTuple) tuplesort_gettuple(state, forward, should_free))
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extern void tuplesort_end(Tuplesortstate *state);
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/*
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* These routines may only be called if randomAccess was specified 'true'.
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* Backwards scan in gettuple is likewise only allowed if randomAccess.
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*/
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extern void tuplesort_rescan(Tuplesortstate *state);
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extern void tuplesort_markpos(Tuplesortstate *state);
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extern void tuplesort_restorepos(Tuplesortstate *state);
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#endif /* TUPLESORT_H */
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