1
/*-------------------------------------------------------------------------
4
* Generalized routines for temporary tuple storage.
6
* This module handles temporary storage of tuples for purposes such
7
* as Materialize nodes, hashjoin batch files, etc. It is essentially
8
* a dumbed-down version of tuplesort.c; it does no sorting of tuples
9
* but can only store and regurgitate a sequence of tuples. However,
10
* because no sort is required, it is allowed to start reading the sequence
11
* before it has all been written. This is particularly useful for cursors,
12
* because it allows random access within the already-scanned portion of
13
* a query without having to process the underlying scan to completion.
14
* Also, it is possible to support multiple independent read pointers.
16
* A temporary file is used to handle the data if it exceeds the
17
* space limit specified by the caller.
19
* Beginning in Postgres 8.2, what is stored is just MinimalTuples;
20
* callers cannot expect valid system columns in regurgitated tuples.
21
* Also, we have changed the API to return tuples in TupleTableSlots,
22
* so that there is a check to prevent attempted access to system columns.
24
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
25
* Portions Copyright (c) 1994, Regents of the University of California
29
*-------------------------------------------------------------------------
34
#include "executor/tuptable.h"
37
/* Tuplestorestate is an opaque type whose details are not known outside
40
typedef struct Tuplestorestate Tuplestorestate;
43
* Currently we only need to store MinimalTuples, but it would be easy
44
* to support the same behavior for IndexTuples and/or bare Datums.
47
extern Tuplestorestate *tuplestore_begin_heap(bool randomAccess,
51
extern void tuplestore_set_eflags(Tuplestorestate *state, int eflags);
53
extern void tuplestore_puttupleslot(Tuplestorestate *state,
54
TupleTableSlot *slot);
55
extern void tuplestore_puttuple(Tuplestorestate *state, HeapTuple tuple);
56
extern void tuplestore_putvalues(Tuplestorestate *state, TupleDesc tdesc,
57
Datum *values, bool *isnull);
59
/* tuplestore_donestoring() used to be required, but is no longer used */
60
#define tuplestore_donestoring(state) ((void) 0)
62
extern int tuplestore_alloc_read_pointer(Tuplestorestate *state, int eflags);
64
extern void tuplestore_select_read_pointer(Tuplestorestate *state, int ptr);
66
extern void tuplestore_copy_read_pointer(Tuplestorestate *state,
67
int srcptr, int destptr);
69
extern void tuplestore_trim(Tuplestorestate *state);
71
extern bool tuplestore_in_memory(Tuplestorestate *state);
73
extern bool tuplestore_gettupleslot(Tuplestorestate *state, bool forward,
74
bool copy, TupleTableSlot *slot);
75
extern bool tuplestore_advance(Tuplestorestate *state, bool forward);
77
extern bool tuplestore_ateof(Tuplestorestate *state);
79
extern void tuplestore_rescan(Tuplestorestate *state);
81
extern void tuplestore_clear(Tuplestorestate *state);
83
extern void tuplestore_end(Tuplestorestate *state);
85
#endif /* TUPLESTORE_H */