executils.c

关系型数据库 Postgresql 6.5.2

 *		the following scan type support functions are for
 *		those nodes which are stubborn and return tuples in
 *		their Scan tuple slot instead of their Result tuple
 *		slot..	luck fur us, these nodes do not do projections
 *		so we don't have to worry about getting the ProjectionInfo
 *		right for them...  -cim 6/3/91
 * ----------------------------------------------------------------
 */

/* ----------------
 *		ExecGetScanType
 * ----------------
 */
TupleDesc
ExecGetScanType(CommonScanState *csstate)
{
	TupleTableSlot *slot = csstate->css_ScanTupleSlot;

	return slot->ttc_tupleDescriptor;
}

/* ----------------
 *		ExecFreeScanType
 * ----------------
 */
#ifdef NOT_USED
void
ExecFreeScanType(CommonScanState *csstate)
{
	TupleTableSlot *slot;
	TupleDesc	tupType;

	slot = csstate->css_ScanTupleSlot;
	tupType = slot->ttc_tupleDescriptor;

	ExecFreeTypeInfo(tupType);
}

#endif

/* ----------------
 *		ExecAssignScanType
 * ----------------
 */
void
ExecAssignScanType(CommonScanState *csstate,
				   TupleDesc tupDesc)
{
	TupleTableSlot *slot;

	slot = (TupleTableSlot *) csstate->css_ScanTupleSlot;
	slot->ttc_tupleDescriptor = tupDesc;
}

/* ----------------
 *		ExecAssignScanTypeFromOuterPlan
 * ----------------
 */
void
ExecAssignScanTypeFromOuterPlan(Plan *node, CommonScanState *csstate)
{
	Plan	   *outerPlan;
	TupleDesc	tupDesc;

	outerPlan = outerPlan(node);
	tupDesc = ExecGetTupType(outerPlan);

	ExecAssignScanType(csstate, tupDesc);
}


/* ----------------------------------------------------------------
 *		ExecTypeFromTL support routines.
 *
 *		these routines are used mainly from ExecTypeFromTL.
 *		-cim 6/12/90
 *
 * old comments
 *		Routines dealing with the structure 'attribute' which conatains
 *		the type information about attributes in a tuple:
 *
 *		ExecMakeTypeInfo(noType)
 *				returns pointer to array of 'noType' structure 'attribute'.
 *		ExecSetTypeInfo(index, typeInfo, attNum, attLen)
 *				sets the element indexed by 'index' in typeInfo with
 *				the values: attNum, attLen.
 *		ExecFreeTypeInfo(typeInfo)
 *				frees the structure 'typeInfo'.
 * ----------------------------------------------------------------
 */

/* ----------------
 *		ExecSetTypeInfo
 *
 *		This initializes fields of a single attribute in a
 *		tuple descriptor from the specified parameters.
 *
 *		XXX this duplicates much of the functionality of TupleDescInitEntry.
 *			the routines should be moved to the same place and be rewritten
 *			to share common code.
 * ----------------
 */
#ifdef NOT_USED
void
ExecSetTypeInfo(int index,
				TupleDesc typeInfo,
				Oid typeID,
				int attNum,
				int attLen,
				char *attName,
				bool attbyVal,
				char attalign)
{
	Form_pg_attribute att;

	/* ----------------
	 *	get attribute pointer and preform a sanity check..
	 * ----------------
	 */
	att = typeInfo[index];
	if (att == NULL)
		elog(ERROR, "ExecSetTypeInfo: trying to assign through NULL");

	/* ----------------
	 *	assign values to the tuple descriptor, being careful not
	 *	to copy a null attName..
	 *
	 *	XXX it is unknown exactly what information is needed to
	 *		initialize the attribute struct correctly so for now
	 *		we use 0.  this should be fixed -- otherwise we run the
	 *		risk of using garbage data. -cim 5/5/91
	 * ----------------
	 */
	att->attrelid = 0;			/* dummy value */

	if (attName != (char *) NULL)
		StrNCpy(att->attname.data, attName, NAMEDATALEN);
	else
		MemSet(att->attname.data, 0, NAMEDATALEN);

	att->atttypid = typeID;
	att->attdefrel = 0;			/* dummy value */
	att->attdisbursion = 0;		/* dummy value */
	att->atttyparg = 0;			/* dummy value */
	att->attlen = attLen;
	att->attnum = attNum;
	att->attbound = 0;			/* dummy value */
	att->attbyval = attbyVal;
	att->attcanindex = 0;		/* dummy value */
	att->attproc = 0;			/* dummy value */
	att->attnelems = 0;			/* dummy value */
	att->attcacheoff = -1;
	att->atttypmod = -1;
	att->attisset = false;
	att->attalign = attalign;
}

/* ----------------
 *		ExecFreeTypeInfo frees the array of attrbutes
 *		created by ExecMakeTypeInfo and returned by ExecTypeFromTL...
 * ----------------
 */
void
ExecFreeTypeInfo(TupleDesc typeInfo)
{
	/* ----------------
	 *	do nothing if asked to free a null pointer
	 * ----------------
	 */
	if (typeInfo == NULL)
		return;

	/* ----------------
	 *	the entire array of typeinfo pointers created by
	 *	ExecMakeTypeInfo was allocated with a single palloc()
	 *	so we can deallocate the whole array with a single pfree().
	 *	(we should not try and free all the elements in the array)
	 *	-cim 6/12/90
	 * ----------------
	 */
	pfree(typeInfo);
}


/* ----------------------------------------------------------------
 *		QueryDescGetTypeInfo
 *
 *|		I don't know how this is used, all I know is that it
 *|		appeared one day in main.c so I moved it here. -cim 11/1/89
 * ----------------------------------------------------------------
 */
TupleDesc
QueryDescGetTypeInfo(QueryDesc *queryDesc)
{
	Plan	   *plan;
	TupleDesc	tupleType;
	List	   *targetList;
	AttrInfo   *attinfo = (AttrInfo *) palloc(sizeof(AttrInfo));

	plan = queryDesc->plantree;
	tupleType = (TupleDesc) ExecGetTupType(plan);
/*
	targetList =  plan->targetlist;

	attinfo->numAttr = ExecTargetListLength(targetList);
	attinfo->attrs = tupleType;
*/
	attinfo->numAttr = tupleType->natts;
	attinfo->attrs = tupleType->attrs;
	return attinfo;
}

#endif

/* ----------------------------------------------------------------
 *				  ExecInsertIndexTuples support
 * ----------------------------------------------------------------
 */
/* ----------------------------------------------------------------
 *		ExecGetIndexKeyInfo
 *
 *		Extracts the index key attribute numbers from
 *		an index tuple form (i.e. a tuple from the pg_index relation)
 *		into an array of attribute numbers.  The array and the
 *		size of the array are returned to the caller via return
 *		parameters.
 * ----------------------------------------------------------------
 */
static void
ExecGetIndexKeyInfo(Form_pg_index indexTuple,
					int *numAttsOutP,
					AttrNumber **attsOutP,
					FuncIndexInfoPtr fInfoP)
{
	int			i;
	int			numKeys;
	AttrNumber *attKeys;

	/* ----------------
	 *	check parameters
	 * ----------------
	 */
	if (numAttsOutP == NULL && attsOutP == NULL)
	{
		elog(DEBUG, "ExecGetIndexKeyInfo: %s",
		"invalid parameters: numAttsOutP and attsOutP must be non-NULL");
	}

	/* ----------------
	 * set the procid for a possible functional index.
	 * ----------------
	 */
	FIsetProcOid(fInfoP, indexTuple->indproc);

	/* ----------------
	 *	count the number of keys..
	 * ----------------
	 */
	numKeys = 0;
	for (i = 0; i < INDEX_MAX_KEYS &&
		 indexTuple->indkey[i] != InvalidAttrNumber; i++)
		numKeys++;

	/* ----------------
	 *	place number keys in callers return area
	 *	or the number of arguments for a functional index.
	 *
	 *	If we have a functional index then the number of
	 *	attributes defined in the index must 1 (the function's
	 *	single return value).
	 * ----------------
	 */
	if (FIgetProcOid(fInfoP) != InvalidOid)
	{
		FIsetnArgs(fInfoP, numKeys);
		(*numAttsOutP) = 1;
	}
	else
		(*numAttsOutP) = numKeys;

	if (numKeys < 1)
	{
		elog(DEBUG, "ExecGetIndexKeyInfo: %s",
			 "all index key attribute numbers are zero!");
		(*attsOutP) = NULL;
		return;
	}

	/* ----------------
	 *	allocate and fill in array of key attribute numbers
	 * ----------------
	 */
	CXT1_printf("ExecGetIndexKeyInfo: context is %d\n", CurrentMemoryContext);

	attKeys = (AttrNumber *) palloc(numKeys * sizeof(AttrNumber));

	for (i = 0; i < numKeys; i++)
		attKeys[i] = indexTuple->indkey[i];

	/* ----------------
	 *	return array to caller.
	 * ----------------
	 */
	(*attsOutP) = attKeys;
}

/* ----------------------------------------------------------------
 *		ExecOpenIndices
 *
 *		Here we scan the pg_index relation to find indices
 *		associated with a given heap relation oid.	Since we
 *		don't know in advance how many indices we have, we
 *		form lists containing the information we need from
 *		pg_index and then process these lists.
 *
 *		Note: much of this code duplicates effort done by
 *		the IndexCatalogInformation function in plancat.c
 *		because IndexCatalogInformation is poorly written.
 *
 *		It would be much better if the functionality provided
 *		by this function and IndexCatalogInformation was
 *		in the form of a small set of orthogonal routines..
 *		If you are trying to understand this, I suggest you
 *		look at the code to IndexCatalogInformation and
 *		FormIndexTuple.. -cim 9/27/89
 * ----------------------------------------------------------------
 */
void
ExecOpenIndices(Oid resultRelationOid,
				RelationInfo *resultRelationInfo)
{
	Relation	indexRd;
	HeapScanDesc indexSd;
	ScanKeyData key;
	HeapTuple	tuple;
	Form_pg_index indexStruct;
	Oid			indexOid;
	List	   *oidList;
	List	   *nkeyList;
	List	   *keyList;
	List	   *fiList;
	char	   *predString;
	List	   *predList;
	List	   *indexoid;
	List	   *numkeys;
	List	   *indexkeys;
	List	   *indexfuncs;
	List	   *indexpreds;
	int			len;

	RelationPtr relationDescs;
	IndexInfo **indexInfoArray;
	FuncIndexInfoPtr fInfoP;
	int			numKeyAtts;
	AttrNumber *indexKeyAtts;
	PredInfo   *predicate;
	int			i;

	/* ----------------
	 *	open pg_index
	 * ----------------
	 */
	indexRd = heap_openr(IndexRelationName);

	/* ----------------
	 *	form a scan key
	 * ----------------
	 */
	ScanKeyEntryInitialize(&key, 0, Anum_pg_index_indrelid,
						   F_OIDEQ,
						   ObjectIdGetDatum(resultRelationOid));

	/* ----------------
	 *	scan the index relation, looking for indices for our
	 *	result relation..
	 * ----------------
	 */
	indexSd = heap_beginscan(indexRd,	/* scan desc */
							 false,		/* scan backward flag */
							 SnapshotNow,		/* NOW snapshot */
							 1, /* number scan keys */
							 &key);		/* scan keys */

	oidList = NIL;
	nkeyList = NIL;
	keyList = NIL;
	fiList = NIL;
	predList = NIL;

	while (HeapTupleIsValid(tuple = heap_getnext(indexSd, 0)))
	{

		/* ----------------
		 *	For each index relation we find, extract the information
		 *	we need and store it in a list..
		 *
		 *	first get the oid of the index relation from the tuple
		 * ----------------
		 */
		indexStruct = (Form_pg_index) GETSTRUCT(tuple);
		indexOid = indexStruct->indexrelid;

		/* ----------------
		 * allocate space for functional index information.
		 * ----------------
		 */
		fInfoP = (FuncIndexInfoPtr) palloc(sizeof(*fInfoP));

		/* ----------------
		 *	next get the index key information from the tuple
		 * ----------------
		 */
		ExecGetIndexKeyInfo(indexStruct,
							&numKeyAtts,
							&indexKeyAtts,
							fInfoP);

		/* ----------------
		 *	next get the index predicate from the tuple