istrat.c

关系型数据库 Postgresql 6.5.2

	Assert(RelationIsValid(relation));
	Assert(relation->rd_rel->relkind == RELKIND_INDEX); /* XXX use accessor */
	numattrs = RelationGetNumberOfAttributes(relation);

	Assert(StrategyEvaluationIsValid(evaluation));
	Assert(AttributeNumberIsValid(attributeNumber));
	Assert((attributeNumber >= 1) && (attributeNumber < 1 + numattrs));

	Assert(StrategyNumberIsInBounds(strategy, evaluation->maxStrategy));

	termData.degree = 1;

	strategyMap = IndexStrategyGetStrategyMap(RelationGetIndexStrategy(relation),
											  evaluation->maxStrategy,
											  attributeNumber);

	entry = StrategyMapGetScanKeyEntry(strategyMap, strategy);

	if (RegProcedureIsValid(entry->sk_procedure))
	{
		termData.operatorData[0].strategy = strategy;
		termData.operatorData[0].flags = 0x0;

		return StrategyTermEvaluate(&termData, strategyMap, left, right);
	}


	newStrategy = evaluation->negateTransform->strategy[strategy - 1];
	if (newStrategy != strategy && StrategyNumberIsValid(newStrategy))
	{

		entry = StrategyMapGetScanKeyEntry(strategyMap, newStrategy);

		if (RegProcedureIsValid(entry->sk_procedure))
		{
			termData.operatorData[0].strategy = newStrategy;
			termData.operatorData[0].flags = SK_NEGATE;

			return StrategyTermEvaluate(&termData, strategyMap, left, right);
		}
	}

	newStrategy = evaluation->commuteTransform->strategy[strategy - 1];
	if (newStrategy != strategy && StrategyNumberIsValid(newStrategy))
	{

		entry = StrategyMapGetScanKeyEntry(strategyMap, newStrategy);

		if (RegProcedureIsValid(entry->sk_procedure))
		{
			termData.operatorData[0].strategy = newStrategy;
			termData.operatorData[0].flags = SK_COMMUTE;

			return StrategyTermEvaluate(&termData, strategyMap, left, right);
		}
	}

	newStrategy = evaluation->negateCommuteTransform->strategy[strategy - 1];
	if (newStrategy != strategy && StrategyNumberIsValid(newStrategy))
	{

		entry = StrategyMapGetScanKeyEntry(strategyMap, newStrategy);

		if (RegProcedureIsValid(entry->sk_procedure))
		{
			termData.operatorData[0].strategy = newStrategy;
			termData.operatorData[0].flags = SK_NEGATE | SK_COMMUTE;

			return StrategyTermEvaluate(&termData, strategyMap, left, right);
		}
	}

	if (PointerIsValid(evaluation->expression[strategy - 1]))
	{
		StrategyTerm *termP;

		termP = &evaluation->expression[strategy - 1]->term[0];
		while (PointerIsValid(*termP))
		{
			Index		index;

			for (index = 0; index < (*termP)->degree; index += 1)
			{
				entry = StrategyMapGetScanKeyEntry(strategyMap,
								 (*termP)->operatorData[index].strategy);

				if (!RegProcedureIsValid(entry->sk_procedure))
					break;
			}

			if (index == (*termP)->degree)
				return StrategyTermEvaluate(*termP, strategyMap, left, right);

			termP += 1;
		}
	}

	elog(ERROR, "RelationInvokeStrategy: cannot evaluate strategy %d",
		 strategy);

	/* not reached, just to make compiler happy */
	return FALSE;


}

/* ----------------
 *		OperatorRelationFillScanKeyEntry
 * ----------------
 */
static void
OperatorRelationFillScanKeyEntry(Relation operatorRelation,
								 Oid operatorObjectId,
								 ScanKey entry)
{
	HeapTuple	tuple;
	HeapScanDesc scan = NULL;

	if (!IsBootstrapProcessingMode())
	{
		tuple = SearchSysCacheTuple(OPROID,
									ObjectIdGetDatum(operatorObjectId),
									0, 0, 0);
	}
	else
	{
		ScanKeyData scanKeyData;

		ScanKeyEntryInitialize(&scanKeyData, 0,
							   ObjectIdAttributeNumber,
							   F_OIDEQ,
							   ObjectIdGetDatum(operatorObjectId));

		scan = heap_beginscan(operatorRelation, false, SnapshotNow,
							  1, &scanKeyData);

		tuple = heap_getnext(scan, 0);
	}

	if (!HeapTupleIsValid(tuple))
	{
		if (IsBootstrapProcessingMode())
			heap_endscan(scan);
		elog(ERROR, "OperatorObjectIdFillScanKeyEntry: unknown operator %lu",
			 (uint32) operatorObjectId);
	}

	entry->sk_flags = 0;
	entry->sk_procedure = ((Form_pg_operator) GETSTRUCT(tuple))->oprcode;
	fmgr_info(entry->sk_procedure, &entry->sk_func);
	entry->sk_nargs = entry->sk_func.fn_nargs;

	if (IsBootstrapProcessingMode())
		heap_endscan(scan);

	if (!RegProcedureIsValid(entry->sk_procedure))
	{
		elog(ERROR,
		"OperatorObjectIdFillScanKeyEntry: no procedure for operator %lu",
			 (uint32) operatorObjectId);
	}
}


/*
 * IndexSupportInitialize
 *		Initializes an index strategy and associated support procedures.
 */
void
IndexSupportInitialize(IndexStrategy indexStrategy,
					   RegProcedure *indexSupport,
					   Oid indexObjectId,
					   Oid accessMethodObjectId,
					   StrategyNumber maxStrategyNumber,
					   StrategyNumber maxSupportNumber,
					   AttrNumber maxAttributeNumber)
{
	Relation	relation = NULL;
	HeapScanDesc scan = NULL;
	ScanKeyData entry[2];
	Relation	operatorRelation;
	HeapTuple	tuple;
	StrategyMap map;
	AttrNumber	attributeNumber;
	int			attributeIndex;
	Oid			operatorClassObjectId[MaxIndexAttributeNumber];

	if (!IsBootstrapProcessingMode())
	{
		tuple = SearchSysCacheTuple(INDEXRELID,
									ObjectIdGetDatum(indexObjectId),
									0, 0, 0);
	}
	else
	{
		ScanKeyEntryInitialize(&entry[0], 0, Anum_pg_index_indexrelid,
							   F_OIDEQ,
							   ObjectIdGetDatum(indexObjectId));

		relation = heap_openr(IndexRelationName);
		scan = heap_beginscan(relation, false, SnapshotNow, 1, entry);
		tuple = heap_getnext(scan, 0);
	}

	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "IndexSupportInitialize: corrupted catalogs");

	maxStrategyNumber = AMStrategies(maxStrategyNumber);

	/*
	 * XXX note that the following assumes the INDEX tuple is well formed
	 * and that the *key and *class are 0 terminated.
	 */
	for (attributeIndex = 0; attributeIndex < maxAttributeNumber; attributeIndex++)
	{
		Form_pg_index iform;

		iform = (Form_pg_index) GETSTRUCT(tuple);

		if (!OidIsValid(iform->indkey[attributeIndex]))
		{
			if (attributeIndex == InvalidAttrNumber)
				elog(ERROR, "IndexSupportInitialize: no pg_index tuple");
			break;
		}

		operatorClassObjectId[attributeIndex] = iform->indclass[attributeIndex];
	}

	if (IsBootstrapProcessingMode())
	{
		heap_endscan(scan);
		heap_close(relation);
	}

	/* if support routines exist for this access method, load them */
	if (maxSupportNumber > 0)
	{
		ScanKeyEntryInitialize(&entry[0], 0, Anum_pg_amproc_amid,
							   F_OIDEQ,
							   ObjectIdGetDatum(accessMethodObjectId));

		ScanKeyEntryInitialize(&entry[1], 0, Anum_pg_amproc_amopclaid,
							   F_OIDEQ, 0);

		relation = heap_openr(AccessMethodProcedureRelationName);

		for (attributeNumber = 1; attributeNumber <= maxAttributeNumber;
			 attributeNumber++)
		{
			int16		support;
			Form_pg_amproc aform;
			RegProcedure *loc;

			loc = &indexSupport[((attributeNumber - 1) * maxSupportNumber)];

			for (support = 0; support < maxSupportNumber; ++support)
				loc[support] = InvalidOid;

			entry[1].sk_argument =
				ObjectIdGetDatum(operatorClassObjectId[attributeNumber - 1]);

			scan = heap_beginscan(relation, false, SnapshotNow, 2, entry);

			while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
			{
				aform = (Form_pg_amproc) GETSTRUCT(tuple);
				loc[(aform->amprocnum - 1)] = aform->amproc;
			}

			heap_endscan(scan);
		}
		heap_close(relation);
	}

	ScanKeyEntryInitialize(&entry[0], 0,
						   Anum_pg_amop_amopid,
						   F_OIDEQ,
						   ObjectIdGetDatum(accessMethodObjectId));

	ScanKeyEntryInitialize(&entry[1], 0,
						   Anum_pg_amop_amopclaid,
						   F_OIDEQ, 0);

	relation = heap_openr(AccessMethodOperatorRelationName);
	operatorRelation = heap_openr(OperatorRelationName);

	for (attributeNumber = maxAttributeNumber; attributeNumber > 0;
		 attributeNumber--)
	{
		StrategyNumber strategy;

		entry[1].sk_argument =
			ObjectIdGetDatum(operatorClassObjectId[attributeNumber - 1]);

		map = IndexStrategyGetStrategyMap(indexStrategy,
										  maxStrategyNumber,
										  attributeNumber);

		for (strategy = 1; strategy <= maxStrategyNumber; strategy++)
			ScanKeyEntrySetIllegal(StrategyMapGetScanKeyEntry(map, strategy));

		scan = heap_beginscan(relation, false, SnapshotNow, 2, entry);

		while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
		{
			Form_pg_amop aform;

			aform = (Form_pg_amop) GETSTRUCT(tuple);
			OperatorRelationFillScanKeyEntry(operatorRelation,
											 aform->amopopr,
					StrategyMapGetScanKeyEntry(map, aform->amopstrategy));
		}

		heap_endscan(scan);
	}

	heap_close(operatorRelation);
	heap_close(relation);
}

/* ----------------
 *		IndexStrategyDisplay
 * ----------------
 */
#ifdef	ISTRATDEBUG
int
IndexStrategyDisplay(IndexStrategy indexStrategy,
					 StrategyNumber numberOfStrategies,
					 int numberOfAttributes)
{
	StrategyMap strategyMap;
	AttrNumber	attributeNumber;
	StrategyNumber strategyNumber;

	for (attributeNumber = 1; attributeNumber <= numberOfAttributes;
		 attributeNumber += 1)
	{

		strategyMap = IndexStrategyGetStrategyMap(indexStrategy,
												  numberOfStrategies,
												  attributeNumber);

		for (strategyNumber = 1;
			 strategyNumber <= AMStrategies(numberOfStrategies);
			 strategyNumber += 1)
		{

			printf(":att %d\t:str %d\t:opr 0x%x(%d)\n",
				   attributeNumber, strategyNumber,
				   strategyMap->entry[strategyNumber - 1].sk_procedure,
				   strategyMap->entry[strategyNumber - 1].sk_procedure);
		}
	}
}

#endif	 /* defined(ISTRATDEBUG) */