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postgresql/src/include/utils/tuplestore.h

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Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
/*-------------------------------------------------------------------------
*
* 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
Revise tuplestore and nodeMaterial so that we don't have to read the entire contents of the subplan into the tuplestore before we can return any tuples. Instead, the tuplestore holds what we've already read, and we fetch additional rows from the subplan as needed. Random access to the previously-read rows works with the tuplestore, and doesn't affect the state of the partially-read subplan. This is a step towards fixing the problems with cursors over complex queries --- we don't want to stick in Materialize nodes if they'll prevent quick startup for a cursor.
2003-03-09 03:19:13 +01:00
* 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.
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
* A temporary file is used to handle the data if it exceeds the
* space limit specified by the caller.
*
Update copyright to 2002.
2002-06-20 22:29:54 +02:00
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
* Portions Copyright (c) 1994, Regents of the University of California
*
tuplestore_donestoring() isn't needed anymore, but provide a no-op macro definition so as not to create compatibility problems.
2003-03-09 04:34:10 +01:00
* $Id: tuplestore.h,v 1.9 2003/03/09 03:34:10 tgl Exp $
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
*
*-------------------------------------------------------------------------
*/
#ifndef TUPLESTORE_H
#define TUPLESTORE_H
#include "access/htup.h"
/* Tuplestorestate is an opaque type whose details are not known outside
* tuplestore.c.
*/
typedef struct Tuplestorestate Tuplestorestate;
/*
* Currently we only need to store HeapTuples, but it would be easy
* to support the same behavior for IndexTuples and/or bare Datums.
*/
extern Tuplestorestate *tuplestore_begin_heap(bool randomAccess,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
int maxKBytes);
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
extern void tuplestore_puttuple(Tuplestorestate *state, void *tuple);
tuplestore_donestoring() isn't needed anymore, but provide a no-op macro definition so as not to create compatibility problems.
2003-03-09 04:34:10 +01:00
/* tuplestore_donestoring() used to be required, but is no longer used */
#define tuplestore_donestoring(state) ((void) 0)
Revise tuplestore and nodeMaterial so that we don't have to read the entire contents of the subplan into the tuplestore before we can return any tuples. Instead, the tuplestore holds what we've already read, and we fetch additional rows from the subplan as needed. Random access to the previously-read rows works with the tuplestore, and doesn't affect the state of the partially-read subplan. This is a step towards fixing the problems with cursors over complex queries --- we don't want to stick in Materialize nodes if they'll prevent quick startup for a cursor.
2003-03-09 03:19:13 +01:00
/* backwards scan is only allowed if randomAccess was specified 'true' */
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
extern void *tuplestore_gettuple(Tuplestorestate *state, bool forward,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
bool *should_free);
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
#define tuplestore_getheaptuple(state, forward, should_free) \
((HeapTuple) tuplestore_gettuple(state, forward, should_free))
extern void tuplestore_end(Tuplestorestate *state);
Revise tuplestore and nodeMaterial so that we don't have to read the entire contents of the subplan into the tuplestore before we can return any tuples. Instead, the tuplestore holds what we've already read, and we fetch additional rows from the subplan as needed. Random access to the previously-read rows works with the tuplestore, and doesn't affect the state of the partially-read subplan. This is a step towards fixing the problems with cursors over complex queries --- we don't want to stick in Materialize nodes if they'll prevent quick startup for a cursor.
2003-03-09 03:19:13 +01:00
extern bool tuplestore_ateof(Tuplestorestate *state);
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
extern void tuplestore_rescan(Tuplestorestate *state);
extern void tuplestore_markpos(Tuplestorestate *state);
extern void tuplestore_restorepos(Tuplestorestate *state);
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments.
2001-10-28 07:26:15 +01:00
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 18:46:40 +01:00
#endif /* TUPLESTORE_H */