254 lines
12 KiB
C
254 lines
12 KiB
C
/* -------------------------------------------------------------------------
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*
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* tuptable.h
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* tuple table support stuff
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*
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*
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* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/executor/tuptable.h
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*
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* -------------------------------------------------------------------------
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*/
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#ifndef TUPTABLE_H
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#define TUPTABLE_H
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#include "access/htup.h"
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#include "storage/buf/buf.h"
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#ifndef FRONTEND_PARSER
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/* ----------
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* The executor stores tuples in a "tuple table" which is a List of
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* independent TupleTableSlots. There are several cases we need to handle:
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* 1. physical tuple in a disk buffer page
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* 2. physical tuple constructed in palloc'ed memory
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* 3. "minimal" physical tuple constructed in palloc'ed memory
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* 4. "virtual" tuple consisting of Datum/isnull arrays
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*
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* The first two cases are similar in that they both deal with "materialized"
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* tuples, but resource management is different. For a tuple in a disk page
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* we need to hold a pin on the buffer until the TupleTableSlot's reference
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* to the tuple is dropped; while for a palloc'd tuple we usually want the
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* tuple pfree'd when the TupleTableSlot's reference is dropped.
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*
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* A "minimal" tuple is handled similarly to a palloc'd regular tuple.
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* At present, minimal tuples never are stored in buffers, so there is no
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* parallel to case 1. Note that a minimal tuple has no "system columns".
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* (Actually, it could have an OID, but we have no need to access the OID.)
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*
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* A "virtual" tuple is an optimization used to minimize physical data
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* copying in a nest of plan nodes. Any pass-by-reference Datums in the
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* tuple point to storage that is not directly associated with the
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* TupleTableSlot; generally they will point to part of a tuple stored in
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* a lower plan node's output TupleTableSlot, or to a function result
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* constructed in a plan node's per-tuple econtext. It is the responsibility
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* of the generating plan node to be sure these resources are not released
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* for as long as the virtual tuple needs to be valid. We only use virtual
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* tuples in the result slots of plan nodes --- tuples to be copied anywhere
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* else need to be "materialized" into physical tuples. Note also that a
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* virtual tuple does not have any "system columns".
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*
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* It is also possible for a TupleTableSlot to hold both physical and minimal
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* copies of a tuple. This is done when the slot is requested to provide
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* the format other than the one it currently holds. (Originally we attempted
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* to handle such requests by replacing one format with the other, but that
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* had the fatal defect of invalidating any pass-by-reference Datums pointing
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* into the existing slot contents.) Both copies must contain identical data
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* payloads when this is the case.
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*
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* The Datum/isnull arrays of a TupleTableSlot serve double duty. When the
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* slot contains a virtual tuple, they are the authoritative data. When the
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* slot contains a physical tuple, the arrays contain data extracted from
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* the tuple. (In this state, any pass-by-reference Datums point into
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* the physical tuple.) The extracted information is built "lazily",
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* ie, only as needed. This serves to avoid repeated extraction of data
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* from the physical tuple.
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*
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* A TupleTableSlot can also be "empty", indicated by flag TTS_EMPTY set in
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* tts_flags, holding no valid data. This is the only valid state for a
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* freshly-created slot that has not yet had a tuple descriptor assigned to it.
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* In this state, TTS_SHOULDFREE should not be set in tts_flag, tts_tuple must
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* be NULL, tts_buffer InvalidBuffer, and tts_nvalid zero.
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*
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* The tupleDescriptor is simply referenced, not copied, by the TupleTableSlot
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* code. The caller of ExecSetSlotDescriptor() is responsible for providing
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* a descriptor that will live as long as the slot does. (Typically, both
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* slots and descriptors are in per-query memory and are freed by memory
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* context deallocation at query end; so it's not worth providing any extra
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* mechanism to do more. However, the slot will increment the tupdesc
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* reference count if a reference-counted tupdesc is supplied.)
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*
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* When TTS_SHOULDFREE is set in tts_flags, the physical tuple is "owned" by
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* the slot and should be freed when the slot's reference to the tuple is
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* dropped.
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*
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* If tts_buffer is not InvalidBuffer, then the slot is holding a pin
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* on the indicated buffer page; drop the pin when we release the
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* slot's reference to that buffer. (tts_shouldFree should always be
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* false in such a case, since presumably tts_tuple is pointing at the
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* buffer page.)
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*
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* tts_nvalid indicates the number of valid columns in the tts_values/isnull
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* arrays. When the slot is holding a "virtual" tuple this must be equal
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* to the descriptor's natts. When the slot is holding a physical tuple
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* this is equal to the number of columns we have extracted (we always
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* extract columns from left to right, so there are no holes).
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*
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* tts_values/tts_isnull are allocated when a descriptor is assigned to the
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* slot; they are of length equal to the descriptor's natts.
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*
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* tts_mintuple must always be NULL if the slot does not hold a "minimal"
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* tuple. When it does, tts_mintuple points to the actual MinimalTupleData
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* object (the thing to be pfree'd if tts_shouldFreeMin is true). If the slot
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* has only a minimal and not also a regular physical tuple, then tts_tuple
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* points at tts_minhdr and the fields of that struct are set correctly
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* for access to the minimal tuple; in particular, tts_minhdr.t_data points
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* MINIMAL_TUPLE_OFFSET bytes before tts_mintuple. This allows column
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* extraction to treat the case identically to regular physical tuples.
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*
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* TTS_SLOW flag in tts_flags and tts_off are saved state for
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* slot_deform_tuple, and should not be touched by any other code.
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* ----------
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*/
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/* true = slot is empty */
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#define TTS_FLAG_EMPTY (1 << 1)
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#define TTS_EMPTY(slot) (((slot)->tts_flags & TTS_FLAG_EMPTY) != 0)
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/* should pfree tts_tuple? */
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#define TTS_FLAG_SHOULDFREE (1 << 2)
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#define TTS_SHOULDFREE(slot) (((slot)->tts_flags & TTS_FLAG_SHOULDFREE) != 0)
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/* should pfree tts_mintuple? */
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#define TTS_FLAG_SHOULDFREEMIN (1 << 3)
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#define TTS_SHOULDFREEMIN(slot) (((slot)->tts_flags & TTS_FLAG_SHOULDFREEMIN) != 0)
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/* saved state for slot_deform_tuple */
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#define TTS_FLAG_SLOW (1 << 4)
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#define TTS_SLOW(slot) (((slot)->tts_flags & TTS_FLAG_SLOW) != 0)
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/* openGauss flags */
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/* should pfree should pfree tts_dataRow? */
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#define TTS_FLAG_SHOULDFREE_ROW (1 << 12)
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#define TTS_SHOULDFREE_ROW(slot) (((slot)->tts_flags & TTS_FLAG_SHOULDFREE_ROW) != 0)
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typedef struct TupleTableSlot {
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NodeTag type;
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uint16 tts_flags; /* Boolean states */
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int tts_nvalid; /* # of valid values in tts_values */
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const TableAmRoutine* tts_tam_ops; /* implementation of table AM */
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Tuple tts_tuple; /* physical tuple, or NULL if virtual */
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TupleDesc tts_tupleDescriptor; /* slot's tuple descriptor */
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MemoryContext tts_mcxt; /* slot itself is in this context */
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Buffer tts_buffer; /* tuple's buffer, or InvalidBuffer */
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long tts_off; /* saved state for slot_deform_tuple */
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Datum* tts_values; /* current per-attribute values */
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bool* tts_isnull; /* current per-attribute isnull flags */
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MinimalTuple tts_mintuple; /* minimal tuple, or NULL if none */
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HeapTupleData tts_minhdr; /* workspace for minimal-tuple-only case */
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long tts_meta_off; /* saved state for slot_deform_cmpr_tuple */
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Datum* tts_lobPointers;
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#ifdef PGXC
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/*
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* PGXC extension to support tuples sent from remote Datanode.
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*/
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char* tts_dataRow; /* Tuple data in DataRow format */
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int tts_dataLen; /* Actual length of the data row */
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struct AttInMetadata* tts_attinmeta; /* store here info to extract values from the DataRow */
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Oid tts_xcnodeoid; /* Oid of node from where the datarow is fetched */
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MemoryContext tts_per_tuple_mcxt;
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#endif
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TableAmType tts_tupslotTableAm; /* slots's tuple table type */
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bool tts_ndpAggHandled; /* slot is from ndp backend, handled by aggregate */
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} TupleTableSlot;
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#define TTS_HAS_PHYSICAL_TUPLE(slot) ((slot)->tts_tuple != NULL && (slot)->tts_tuple != &((slot)->tts_minhdr))
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#define TTS_TABLEAM_IS_HEAP(slot) ((slot)->tts_tam_ops == TableAmHeap)
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#define TTS_TABLEAM_IS_USTORE(slot) ((slot)->tts_tam_ops == TableAmUstore)
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/*
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* TupIsNull -- is a TupleTableSlot empty?
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*/
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#define TupIsNull(slot) ((slot) == NULL || TTS_EMPTY(slot))
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/* in executor/execTuples.c */
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extern TupleTableSlot* MakeTupleTableSlot(bool has_tuple_mcxt = false, const TableAmRoutine* tam_ops = TableAmHeap);
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extern TupleTableSlot* ExecAllocTableSlot(List** tupleTable, const TableAmRoutine* tam_ops = TableAmHeap);
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extern void ExecResetTupleTable(List* tupleTable, bool shouldFree);
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extern TupleTableSlot* MakeSingleTupleTableSlot(TupleDesc tupdesc, bool allocSlotCxt = false, const TableAmRoutine* tam_ops = TableAmHeap);
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extern void ExecDropSingleTupleTableSlot(TupleTableSlot* slot);
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extern void ExecSetSlotDescriptor(TupleTableSlot* slot, TupleDesc tupdesc);
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extern TupleTableSlot* ExecStoreTuple(Tuple tuple, TupleTableSlot* slot, Buffer buffer, bool shouldFree);
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extern TupleTableSlot *ExecStoreTupleBatch(HeapTuple tuple, TupleTableSlot *slot,
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Buffer buffer, bool shouldFree, int rownum);
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extern TupleTableSlot* ExecStoreMinimalTuple(MinimalTuple mtup, TupleTableSlot* slot, bool shouldFree);
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#ifdef PGXC
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extern TupleTableSlot* ExecStoreDataRowTuple(
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char* msg, size_t len, Oid msgnode_oid, TupleTableSlot* slot, bool shouldFree);
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#endif
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extern TupleTableSlot* ExecClearTuple(TupleTableSlot* slot);
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extern void ExecClearMutilTuple(List* slots);
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/* --------------------------------
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* ExecStoreVirtualTuple
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* Mark a slot as containing a virtual tuple.
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*
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* The protocol for loading a slot with virtual tuple data is:
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* * Call ExecClearTuple to mark the slot empty.
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* * Store data into the Datum/isnull arrays.
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* * Call ExecStoreVirtualTuple to mark the slot valid.
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* This is a bit unclean but it avoids one round of data copying.
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* --------------------------------
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*/
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inline TupleTableSlot* ExecStoreVirtualTuple(TupleTableSlot* slot)
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{
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/*
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* sanity checks
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*/
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Assert(slot != NULL);
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Assert(slot->tts_tupleDescriptor != NULL);
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Assert(TTS_EMPTY(slot));
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slot->tts_flags &= ~TTS_FLAG_EMPTY;
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slot->tts_nvalid = slot->tts_tupleDescriptor->natts;
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return slot;
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}
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extern TupleTableSlot* ExecStoreAllNullTuple(TupleTableSlot* slot);
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extern HeapTuple ExecCopySlotTuple(TupleTableSlot* slot);
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extern MinimalTuple ExecCopySlotMinimalTuple(TupleTableSlot* slot, bool need_transform_anyarray = false);
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extern HeapTuple ExecFetchSlotTuple(TupleTableSlot* slot);
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extern MinimalTuple ExecFetchSlotMinimalTuple(TupleTableSlot* slot);
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extern Datum ExecFetchSlotTupleDatum(TupleTableSlot* slot);
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extern HeapTuple ExecMaterializeSlot(TupleTableSlot* slot);
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extern TupleTableSlot* ExecCopySlot(TupleTableSlot* dstslot, TupleTableSlot* srcslot);
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/* heap table specific slot/tuple operations*/
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/* definitions are found in access/common/heaptuple.c */
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extern void heap_slot_clear(TupleTableSlot* slot);
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extern HeapTuple heap_slot_materialize(TupleTableSlot* slot);
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extern MinimalTuple heap_slot_get_minimal_tuple(TupleTableSlot *slot);
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extern MinimalTuple heap_slot_copy_minimal_tuple(TupleTableSlot *slot);
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extern void heap_slot_store_minimal_tuple(MinimalTuple mtup, TupleTableSlot *slot, bool shouldFree);
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extern HeapTuple heap_slot_get_heap_tuple (TupleTableSlot* slot);
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extern HeapTuple heap_slot_copy_heap_tuple (TupleTableSlot *slot);
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extern void heap_slot_store_heap_tuple(Tuple tup, TupleTableSlot* slot, Buffer buffer, bool shouldFree, bool batchMode);
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extern Datum heap_slot_getattr(TupleTableSlot* slot, int attnum, bool* isnull, bool need_transform_anyarray = false);
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extern void heap_slot_getallattrs(TupleTableSlot* slot, bool need_transform_anyarray = false);
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extern void slot_getallattrsfast(TupleTableSlot *slot, int maxIdx);
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extern void heap_slot_getsomeattrs(TupleTableSlot* slot, int attnum);
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extern bool heap_slot_attisnull(TupleTableSlot* slot, int attnum);
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extern void heap_slot_formbatch(TupleTableSlot* slot, struct VectorBatch* batch, int cur_rows, int attnum);
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#endif /* !FRONTEND_PARSER */
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#endif /* TUPTABLE_H */
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