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/*-------------------------------------------------------------------------
*
* tuplestore.h
* Generalized routines for temporary tuple storage.
*
* This module handles temporary storage of tuples for purposes such
* as Materialize nodes, hashjoin batch files, etc. It is essentially
* a dumbed-down version of tuplesort.c; it does no sorting of tuples
* but can only store and regurgitate a sequence of tuples. However,
* because no sort is required, it is allowed to start reading the sequence
* before it has all been written. This is particularly useful for cursors,
* because it allows random access within the already-scanned portion of
* a query without having to process the underlying scan to completion.
* Also, it is possible to support multiple independent read pointers.
*
* A temporary file is used to handle the data if it exceeds the
* space limit specified by the caller.
*
* Beginning in Postgres 8.2, what is stored is just MinimalTuples;
* callers cannot expect valid system columns in regurgitated tuples.
* Also, we have changed the API to return tuples in TupleTableSlots,
* so that there is a check to prevent attempted access to system columns.
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/tuplestore.h
*
*-------------------------------------------------------------------------
*/
#ifndef TUPLESTORE_H
#define TUPLESTORE_H
#include "executor/tuptable.h"
/* Tuplestorestate is an opaque type whose details are not known outside
* tuplestore.c.
*/
typedef struct Tuplestorestate Tuplestorestate;
/*
* Currently we only need to store MinimalTuples, but it would be easy
* to support the same behavior for IndexTuples and/or bare Datums.
*/
extern Tuplestorestate *tuplestore_begin_heap(bool randomAccess,
bool interXact,
int maxKBytes);
extern void tuplestore_set_eflags(Tuplestorestate *state, int eflags);
extern void tuplestore_puttupleslot(Tuplestorestate *state,
TupleTableSlot *slot);
extern void tuplestore_puttuple(Tuplestorestate *state, HeapTuple tuple);
extern void tuplestore_putvalues(Tuplestorestate *state, TupleDesc tdesc,
Datum *values, bool *isnull);
/* tuplestore_donestoring() used to be required, but is no longer used */
#define tuplestore_donestoring(state) ((void) 0)
extern int tuplestore_alloc_read_pointer(Tuplestorestate *state, int eflags);
extern void tuplestore_select_read_pointer(Tuplestorestate *state, int ptr);
extern void tuplestore_copy_read_pointer(Tuplestorestate *state,
int srcptr, int destptr);
extern void tuplestore_trim(Tuplestorestate *state);
extern bool tuplestore_in_memory(Tuplestorestate *state);
extern bool tuplestore_gettupleslot(Tuplestorestate *state, bool forward,
bool copy, TupleTableSlot *slot);
extern bool tuplestore_advance(Tuplestorestate *state, bool forward);
extern bool tuplestore_skiptuples(Tuplestorestate *state,
int64 ntuples, bool forward);
extern int64 tuplestore_tuple_count(Tuplestorestate *state);
extern bool tuplestore_ateof(Tuplestorestate *state);
extern void tuplestore_rescan(Tuplestorestate *state);
extern void tuplestore_clear(Tuplestorestate *state);
extern void tuplestore_end(Tuplestorestate *state);
#endif /* TUPLESTORE_H */
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