Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 487 insertions, 0 deletions

diff --git a/src/include/executor/tuptable.h b/src/include/executor/tuptable.h
new file mode 100644
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--- /dev/null
+++ b/src/include/executor/tuptable.h
@@ -0,0 +1,487 @@
+/*-------------------------------------------------------------------------
+ *
+ * tuptable.h
+ *	  tuple table support stuff
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/executor/tuptable.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef TUPTABLE_H
+#define TUPTABLE_H
+
+#include "access/htup.h"
+#include "access/htup_details.h"
+#include "access/sysattr.h"
+#include "access/tupdesc.h"
+#include "storage/buf.h"
+
+/*----------
+ * The executor stores tuples in a "tuple table" which is a List of
+ * independent TupleTableSlots.
+ *
+ * There's various different types of tuple table slots, each being able to
+ * store different types of tuples. Additional types of slots can be added
+ * without modifying core code. The type of a slot is determined by the
+ * TupleTableSlotOps* passed to the slot creation routine. The builtin types
+ * of slots are
+ *
+ * 1. physical tuple in a disk buffer page (TTSOpsBufferHeapTuple)
+ * 2. physical tuple constructed in palloc'ed memory (TTSOpsHeapTuple)
+ * 3. "minimal" physical tuple constructed in palloc'ed memory
+ *    (TTSOpsMinimalTuple)
+ * 4. "virtual" tuple consisting of Datum/isnull arrays (TTSOpsVirtual)
+ *
+ *
+ * The first two cases are similar in that they both deal with "materialized"
+ * tuples, but resource management is different.  For a tuple in a disk page
+ * we need to hold a pin on the buffer until the TupleTableSlot's reference
+ * to the tuple is dropped; while for a palloc'd tuple we usually want the
+ * tuple pfree'd when the TupleTableSlot's reference is dropped.
+ *
+ * A "minimal" tuple is handled similarly to a palloc'd regular tuple.
+ * At present, minimal tuples never are stored in buffers, so there is no
+ * parallel to case 1.  Note that a minimal tuple has no "system columns".
+ * (Actually, it could have an OID, but we have no need to access the OID.)
+ *
+ * A "virtual" tuple is an optimization used to minimize physical data copying
+ * in a nest of plan nodes.  Until materialized pass-by-reference Datums in
+ * the slot point to storage that is not directly associated with the
+ * TupleTableSlot; generally they will point to part of a tuple stored in a
+ * lower plan node's output TupleTableSlot, or to a function result
+ * constructed in a plan node's per-tuple econtext.  It is the responsibility
+ * of the generating plan node to be sure these resources are not released for
+ * as long as the virtual tuple needs to be valid or is materialized.  Note
+ * also that a virtual tuple does not have any "system columns".
+ *
+ * The Datum/isnull arrays of a TupleTableSlot serve double duty.  For virtual
+ * slots they are the authoritative data.  For the other builtin slots,
+ * the arrays contain data extracted from the tuple.  (In this state, any
+ * pass-by-reference Datums point into the physical tuple.)  The extracted
+ * information is built "lazily", ie, only as needed.  This serves to avoid
+ * repeated extraction of data from the physical tuple.
+ *
+ * A TupleTableSlot can also be "empty", indicated by flag TTS_FLAG_EMPTY set
+ * in tts_flags, holding no valid data.  This is the only valid state for a
+ * freshly-created slot that has not yet had a tuple descriptor assigned to
+ * it.  In this state, TTS_SHOULDFREE should not be set in tts_flags, tts_tuple
+ * must be NULL and tts_nvalid zero.
+ *
+ * The tupleDescriptor is simply referenced, not copied, by the TupleTableSlot
+ * code.  The caller of ExecSetSlotDescriptor() is responsible for providing
+ * a descriptor that will live as long as the slot does.  (Typically, both
+ * slots and descriptors are in per-query memory and are freed by memory
+ * context deallocation at query end; so it's not worth providing any extra
+ * mechanism to do more.  However, the slot will increment the tupdesc
+ * reference count if a reference-counted tupdesc is supplied.)
+ *
+ * When TTS_SHOULDFREE is set in tts_flags, the physical tuple is "owned" by
+ * the slot and should be freed when the slot's reference to the tuple is
+ * dropped.
+ *
+ * tts_values/tts_isnull are allocated either when the slot is created (when
+ * the descriptor is provided), or when a descriptor is assigned to the slot;
+ * they are of length equal to the descriptor's natts.
+ *
+ * The TTS_FLAG_SLOW flag is saved state for
+ * slot_deform_heap_tuple, and should not be touched by any other code.
+ *----------
+ */
+
+/* true = slot is empty */
+#define			TTS_FLAG_EMPTY			(1 << 1)
+#define TTS_EMPTY(slot)	(((slot)->tts_flags & TTS_FLAG_EMPTY) != 0)
+
+/* should pfree tuple "owned" by the slot? */
+#define			TTS_FLAG_SHOULDFREE		(1 << 2)
+#define TTS_SHOULDFREE(slot) (((slot)->tts_flags & TTS_FLAG_SHOULDFREE) != 0)
+
+/* saved state for slot_deform_heap_tuple */
+#define			TTS_FLAG_SLOW		(1 << 3)
+#define TTS_SLOW(slot) (((slot)->tts_flags & TTS_FLAG_SLOW) != 0)
+
+/* fixed tuple descriptor */
+#define			TTS_FLAG_FIXED		(1 << 4)
+#define TTS_FIXED(slot) (((slot)->tts_flags & TTS_FLAG_FIXED) != 0)
+
+struct TupleTableSlotOps;
+typedef struct TupleTableSlotOps TupleTableSlotOps;
+
+/* base tuple table slot type */
+typedef struct TupleTableSlot
+{
+	NodeTag		type;
+#define FIELDNO_TUPLETABLESLOT_FLAGS 1
+	uint16		tts_flags;		/* Boolean states */
+#define FIELDNO_TUPLETABLESLOT_NVALID 2
+	AttrNumber	tts_nvalid;		/* # of valid values in tts_values */
+	const TupleTableSlotOps *const tts_ops; /* implementation of slot */
+#define FIELDNO_TUPLETABLESLOT_TUPLEDESCRIPTOR 4
+	TupleDesc	tts_tupleDescriptor;	/* slot's tuple descriptor */
+#define FIELDNO_TUPLETABLESLOT_VALUES 5
+	Datum	   *tts_values;		/* current per-attribute values */
+#define FIELDNO_TUPLETABLESLOT_ISNULL 6
+	bool	   *tts_isnull;		/* current per-attribute isnull flags */
+	MemoryContext tts_mcxt;		/* slot itself is in this context */
+	ItemPointerData tts_tid;	/* stored tuple's tid */
+	Oid			tts_tableOid;	/* table oid of tuple */
+} TupleTableSlot;
+
+/* routines for a TupleTableSlot implementation */
+struct TupleTableSlotOps
+{
+	/* Minimum size of the slot */
+	size_t		base_slot_size;
+
+	/* Initialization. */
+	void		(*init) (TupleTableSlot *slot);
+
+	/* Destruction. */
+	void		(*release) (TupleTableSlot *slot);
+
+	/*
+	 * Clear the contents of the slot. Only the contents are expected to be
+	 * cleared and not the tuple descriptor. Typically an implementation of
+	 * this callback should free the memory allocated for the tuple contained
+	 * in the slot.
+	 */
+	void		(*clear) (TupleTableSlot *slot);
+
+	/*
+	 * Fill up first natts entries of tts_values and tts_isnull arrays with
+	 * values from the tuple contained in the slot. The function may be called
+	 * with natts more than the number of attributes available in the tuple,
+	 * in which case it should set tts_nvalid to the number of returned
+	 * columns.
+	 */
+	void		(*getsomeattrs) (TupleTableSlot *slot, int natts);
+
+	/*
+	 * Returns value of the given system attribute as a datum and sets isnull
+	 * to false, if it's not NULL. Throws an error if the slot type does not
+	 * support system attributes.
+	 */
+	Datum		(*getsysattr) (TupleTableSlot *slot, int attnum, bool *isnull);
+
+	/*
+	 * Make the contents of the slot solely depend on the slot, and not on
+	 * underlying resources (like another memory context, buffers, etc).
+	 */
+	void		(*materialize) (TupleTableSlot *slot);
+
+	/*
+	 * Copy the contents of the source slot into the destination slot's own
+	 * context. Invoked using callback of the destination slot.
+	 */
+	void		(*copyslot) (TupleTableSlot *dstslot, TupleTableSlot *srcslot);
+
+	/*
+	 * Return a heap tuple "owned" by the slot. It is slot's responsibility to
+	 * free the memory consumed by the heap tuple. If the slot can not "own" a
+	 * heap tuple, it should not implement this callback and should set it as
+	 * NULL.
+	 */
+	HeapTuple	(*get_heap_tuple) (TupleTableSlot *slot);
+
+	/*
+	 * Return a minimal tuple "owned" by the slot. It is slot's responsibility
+	 * to free the memory consumed by the minimal tuple. If the slot can not
+	 * "own" a minimal tuple, it should not implement this callback and should
+	 * set it as NULL.
+	 */
+	MinimalTuple (*get_minimal_tuple) (TupleTableSlot *slot);
+
+	/*
+	 * Return a copy of heap tuple representing the contents of the slot. The
+	 * copy needs to be palloc'd in the current memory context. The slot
+	 * itself is expected to remain unaffected. It is *not* expected to have
+	 * meaningful "system columns" in the copy. The copy is not be "owned" by
+	 * the slot i.e. the caller has to take responsibility to free memory
+	 * consumed by the slot.
+	 */
+	HeapTuple	(*copy_heap_tuple) (TupleTableSlot *slot);
+
+	/*
+	 * Return a copy of minimal tuple representing the contents of the slot.
+	 * The copy needs to be palloc'd in the current memory context. The slot
+	 * itself is expected to remain unaffected. It is *not* expected to have
+	 * meaningful "system columns" in the copy. The copy is not be "owned" by
+	 * the slot i.e. the caller has to take responsibility to free memory
+	 * consumed by the slot.
+	 */
+	MinimalTuple (*copy_minimal_tuple) (TupleTableSlot *slot);
+};
+
+/*
+ * Predefined TupleTableSlotOps for various types of TupleTableSlotOps. The
+ * same are used to identify the type of a given slot.
+ */
+extern PGDLLIMPORT const TupleTableSlotOps TTSOpsVirtual;
+extern PGDLLIMPORT const TupleTableSlotOps TTSOpsHeapTuple;
+extern PGDLLIMPORT const TupleTableSlotOps TTSOpsMinimalTuple;
+extern PGDLLIMPORT const TupleTableSlotOps TTSOpsBufferHeapTuple;
+
+#define TTS_IS_VIRTUAL(slot) ((slot)->tts_ops == &TTSOpsVirtual)
+#define TTS_IS_HEAPTUPLE(slot) ((slot)->tts_ops == &TTSOpsHeapTuple)
+#define TTS_IS_MINIMALTUPLE(slot) ((slot)->tts_ops == &TTSOpsMinimalTuple)
+#define TTS_IS_BUFFERTUPLE(slot) ((slot)->tts_ops == &TTSOpsBufferHeapTuple)
+
+
+/*
+ * Tuple table slot implementations.
+ */
+
+typedef struct VirtualTupleTableSlot
+{
+	TupleTableSlot base;
+
+	char	   *data;			/* data for materialized slots */
+} VirtualTupleTableSlot;
+
+typedef struct HeapTupleTableSlot
+{
+	TupleTableSlot base;
+
+#define FIELDNO_HEAPTUPLETABLESLOT_TUPLE 1
+	HeapTuple	tuple;			/* physical tuple */
+#define FIELDNO_HEAPTUPLETABLESLOT_OFF 2
+	uint32		off;			/* saved state for slot_deform_heap_tuple */
+	HeapTupleData tupdata;		/* optional workspace for storing tuple */
+} HeapTupleTableSlot;
+
+/* heap tuple residing in a buffer */
+typedef struct BufferHeapTupleTableSlot
+{
+	HeapTupleTableSlot base;
+
+	/*
+	 * If buffer is not InvalidBuffer, then the slot is holding a pin on the
+	 * indicated buffer page; drop the pin when we release the slot's
+	 * reference to that buffer.  (TTS_FLAG_SHOULDFREE should not be set in
+	 * such a case, since presumably tts_tuple is pointing into the buffer.)
+	 */
+	Buffer		buffer;			/* tuple's buffer, or InvalidBuffer */
+} BufferHeapTupleTableSlot;
+
+typedef struct MinimalTupleTableSlot
+{
+	TupleTableSlot base;
+
+	/*
+	 * In a minimal slot tuple points at minhdr and the fields of that struct
+	 * are set correctly for access to the minimal tuple; in particular,
+	 * minhdr.t_data points MINIMAL_TUPLE_OFFSET bytes before mintuple.  This
+	 * allows column extraction to treat the case identically to regular
+	 * physical tuples.
+	 */
+#define FIELDNO_MINIMALTUPLETABLESLOT_TUPLE 1
+	HeapTuple	tuple;			/* tuple wrapper */
+	MinimalTuple mintuple;		/* minimal tuple, or NULL if none */
+	HeapTupleData minhdr;		/* workspace for minimal-tuple-only case */
+#define FIELDNO_MINIMALTUPLETABLESLOT_OFF 4
+	uint32		off;			/* saved state for slot_deform_heap_tuple */
+} MinimalTupleTableSlot;
+
+/*
+ * TupIsNull -- is a TupleTableSlot empty?
+ */
+#define TupIsNull(slot) \
+	((slot) == NULL || TTS_EMPTY(slot))
+
+/* in executor/execTuples.c */
+extern TupleTableSlot *MakeTupleTableSlot(TupleDesc tupleDesc,
+										  const TupleTableSlotOps *tts_ops);
+extern TupleTableSlot *ExecAllocTableSlot(List **tupleTable, TupleDesc desc,
+										  const TupleTableSlotOps *tts_ops);
+extern void ExecResetTupleTable(List *tupleTable, bool shouldFree);
+extern TupleTableSlot *MakeSingleTupleTableSlot(TupleDesc tupdesc,
+												const TupleTableSlotOps *tts_ops);
+extern void ExecDropSingleTupleTableSlot(TupleTableSlot *slot);
+extern void ExecSetSlotDescriptor(TupleTableSlot *slot, TupleDesc tupdesc);
+extern TupleTableSlot *ExecStoreHeapTuple(HeapTuple tuple,
+										  TupleTableSlot *slot,
+										  bool shouldFree);
+extern void ExecForceStoreHeapTuple(HeapTuple tuple,
+									TupleTableSlot *slot,
+									bool shouldFree);
+extern TupleTableSlot *ExecStoreBufferHeapTuple(HeapTuple tuple,
+												TupleTableSlot *slot,
+												Buffer buffer);
+extern TupleTableSlot *ExecStorePinnedBufferHeapTuple(HeapTuple tuple,
+													  TupleTableSlot *slot,
+													  Buffer buffer);
+extern TupleTableSlot *ExecStoreMinimalTuple(MinimalTuple mtup,
+											 TupleTableSlot *slot,
+											 bool shouldFree);
+extern void ExecForceStoreMinimalTuple(MinimalTuple mtup, TupleTableSlot *slot,
+									   bool shouldFree);
+extern TupleTableSlot *ExecStoreVirtualTuple(TupleTableSlot *slot);
+extern TupleTableSlot *ExecStoreAllNullTuple(TupleTableSlot *slot);
+extern void ExecStoreHeapTupleDatum(Datum data, TupleTableSlot *slot);
+extern HeapTuple ExecFetchSlotHeapTuple(TupleTableSlot *slot, bool materialize, bool *shouldFree);
+extern MinimalTuple ExecFetchSlotMinimalTuple(TupleTableSlot *slot,
+											  bool *shouldFree);
+extern Datum ExecFetchSlotHeapTupleDatum(TupleTableSlot *slot);
+extern void slot_getmissingattrs(TupleTableSlot *slot, int startAttNum,
+								 int lastAttNum);
+extern void slot_getsomeattrs_int(TupleTableSlot *slot, int attnum);
+
+
+#ifndef FRONTEND
+
+/*
+ * This function forces the entries of the slot's Datum/isnull arrays to be
+ * valid at least up through the attnum'th entry.
+ */
+static inline void
+slot_getsomeattrs(TupleTableSlot *slot, int attnum)
+{
+	if (slot->tts_nvalid < attnum)
+		slot_getsomeattrs_int(slot, attnum);
+}
+
+/*
+ * slot_getallattrs
+ *		This function forces all the entries of the slot's Datum/isnull
+ *		arrays to be valid.  The caller may then extract data directly
+ *		from those arrays instead of using slot_getattr.
+ */
+static inline void
+slot_getallattrs(TupleTableSlot *slot)
+{
+	slot_getsomeattrs(slot, slot->tts_tupleDescriptor->natts);
+}
+
+
+/*
+ * slot_attisnull
+ *
+ * Detect whether an attribute of the slot is null, without actually fetching
+ * it.
+ */
+static inline bool
+slot_attisnull(TupleTableSlot *slot, int attnum)
+{
+	AssertArg(attnum > 0);
+
+	if (attnum > slot->tts_nvalid)
+		slot_getsomeattrs(slot, attnum);
+
+	return slot->tts_isnull[attnum - 1];
+}
+
+/*
+ * slot_getattr - fetch one attribute of the slot's contents.
+ */
+static inline Datum
+slot_getattr(TupleTableSlot *slot, int attnum,
+			 bool *isnull)
+{
+	AssertArg(attnum > 0);
+
+	if (attnum > slot->tts_nvalid)
+		slot_getsomeattrs(slot, attnum);
+
+	*isnull = slot->tts_isnull[attnum - 1];
+
+	return slot->tts_values[attnum - 1];
+}
+
+/*
+ * slot_getsysattr - fetch a system attribute of the slot's current tuple.
+ *
+ *  If the slot type does not contain system attributes, this will throw an
+ *  error.  Hence before calling this function, callers should make sure that
+ *  the slot type is the one that supports system attributes.
+ */
+static inline Datum
+slot_getsysattr(TupleTableSlot *slot, int attnum, bool *isnull)
+{
+	AssertArg(attnum < 0);		/* caller error */
+
+	if (attnum == TableOidAttributeNumber)
+	{
+		*isnull = false;
+		return ObjectIdGetDatum(slot->tts_tableOid);
+	}
+	else if (attnum == SelfItemPointerAttributeNumber)
+	{
+		*isnull = false;
+		return PointerGetDatum(&slot->tts_tid);
+	}
+
+	/* Fetch the system attribute from the underlying tuple. */
+	return slot->tts_ops->getsysattr(slot, attnum, isnull);
+}
+
+/*
+ * ExecClearTuple - clear the slot's contents
+ */
+static inline TupleTableSlot *
+ExecClearTuple(TupleTableSlot *slot)
+{
+	slot->tts_ops->clear(slot);
+
+	return slot;
+}
+
+/* ExecMaterializeSlot - force a slot into the "materialized" state.
+ *
+ * This causes the slot's tuple to be a local copy not dependent on any
+ * external storage (i.e. pointing into a Buffer, or having allocations in
+ * another memory context).
+ *
+ * A typical use for this operation is to prepare a computed tuple for being
+ * stored on disk.  The original data may or may not be virtual, but in any
+ * case we need a private copy for heap_insert to scribble on.
+ */
+static inline void
+ExecMaterializeSlot(TupleTableSlot *slot)
+{
+	slot->tts_ops->materialize(slot);
+}
+
+/*
+ * ExecCopySlotHeapTuple - return HeapTuple allocated in caller's context
+ */
+static inline HeapTuple
+ExecCopySlotHeapTuple(TupleTableSlot *slot)
+{
+	Assert(!TTS_EMPTY(slot));
+
+	return slot->tts_ops->copy_heap_tuple(slot);
+}
+
+/*
+ * ExecCopySlotMinimalTuple - return MinimalTuple allocated in caller's context
+ */
+static inline MinimalTuple
+ExecCopySlotMinimalTuple(TupleTableSlot *slot)
+{
+	return slot->tts_ops->copy_minimal_tuple(slot);
+}
+
+/*
+ * ExecCopySlot - copy one slot's contents into another.
+ *
+ * If a source's system attributes are supposed to be accessed in the target
+ * slot, the target slot and source slot types need to match.
+ */
+static inline TupleTableSlot *
+ExecCopySlot(TupleTableSlot *dstslot, TupleTableSlot *srcslot)
+{
+	Assert(!TTS_EMPTY(srcslot));
+	AssertArg(srcslot != dstslot);
+
+	dstslot->tts_ops->copyslot(dstslot, srcslot);
+
+	return dstslot;
+}
+
+#endif							/* FRONTEND */
+
+#endif							/* TUPTABLE_H */