selfuncs.c

关系型数据库 Postgresql 6.5.2

								 &isnull));
	if (isnull)
		elog(DEBUG, "gethilokey: high key is null");
	*low = textout((struct varlena *)
				   heap_getattr(tuple,
								Anum_pg_statistic_stalokey,
								RelationGetDescr(rel),
								&isnull));
	if (isnull)
		elog(DEBUG, "gethilokey: low key is null");
	heap_endscan(scan);
	heap_close(rel);
}

float64
btreesel(Oid operatorObjectId,
		 Oid indrelid,
		 AttrNumber attributeNumber,
		 char *constValue,
		 int32 constFlag,
		 int32 nIndexKeys,
		 Oid indexrelid)
{
	float64		result;

	if (FunctionalSelectivity(nIndexKeys, attributeNumber))
	{

		/*
		 * Need to call the functions selectivity function here.  For now
		 * simply assume it's 1/3 since functions don't currently have
		 * selectivity functions
		 */
		result = (float64) palloc(sizeof(float64data));
		*result = 1.0 / 3.0;
	}
	else
	{
		RegProcedure oprrest = get_oprrest(operatorObjectId);

		/*
		 * Operators used for indexes should have selectivity estimators.
		 * (An alternative is to default to 0.5, as the optimizer does in
		 * dealing with operators occurring in WHERE clauses, but if you
		 * are going to the trouble of making index support you probably
		 * don't want to miss the benefits of a good selectivity estimate.)
		 */
		if (!oprrest)
		{
#if 1
			/*
			 * XXX temporary fix for 6.5: rtree operators are missing their
			 * selectivity estimators, so return a default estimate instead.
			 * Ugh.
			 */
			result = (float64) palloc(sizeof(float64data));
			*result = 0.5;
#else
			elog(ERROR,
				 "Operator %u must have a restriction selectivity estimator to be used in an index",
				 operatorObjectId);
#endif
		}
		else
			result = (float64) fmgr(oprrest,
									(char *) operatorObjectId,
									(char *) indrelid,
									(char *) (int) attributeNumber,
									(char *) constValue,
									(char *) constFlag,
									NULL);
	}

	if (!PointerIsValid(result))
		elog(ERROR, "Btree Selectivity: bad pointer");
	if (*result < 0.0 || *result > 1.0)
		elog(ERROR, "Btree Selectivity: bad value %lf", *result);

	return result;
}

float64
btreenpage(Oid operatorObjectId,
		   Oid indrelid,
		   AttrNumber attributeNumber,
		   char *constValue,
		   int32 constFlag,
		   int32 nIndexKeys,
		   Oid indexrelid)
{
	float64		temp,
				result;
	float64data tempData;
	HeapTuple	atp;
	int			npage;

	if (FunctionalSelectivity(nIndexKeys, attributeNumber))
	{

		/*
		 * Need to call the functions selectivity function here.  For now
		 * simply assume it's 1/3 since functions don't currently have
		 * selectivity functions
		 */
		tempData = 1.0 / 3.0;
		temp = &tempData;
	}
	else
	{
		RegProcedure oprrest = get_oprrest(operatorObjectId);

		/*
		 * Operators used for indexes should have selectivity estimators.
		 * (An alternative is to default to 0.5, as the optimizer does in
		 * dealing with operators occurring in WHERE clauses, but if you
		 * are going to the trouble of making index support you probably
		 * don't want to miss the benefits of a good selectivity estimate.)
		 */
		if (!oprrest)
		{
#if 1
			/*
			 * XXX temporary fix for 6.5: rtree operators are missing their
			 * selectivity estimators, so return a default estimate instead.
			 * Ugh.
			 */
			tempData = 0.5;
			temp = &tempData;
#else
			elog(ERROR,
				 "Operator %u must have a restriction selectivity estimator to be used in an index",
				 operatorObjectId);
#endif
		}
		else
			temp = (float64) fmgr(oprrest,
								  (char *) operatorObjectId,
								  (char *) indrelid,
								  (char *) (int) attributeNumber,
								  (char *) constValue,
								  (char *) constFlag,
								  NULL);
	}

	atp = SearchSysCacheTuple(RELOID,
							  ObjectIdGetDatum(indexrelid),
							  0, 0, 0);
	if (!HeapTupleIsValid(atp))
	{
		elog(ERROR, "btreenpage: no index tuple %u", indexrelid);
		return 0;
	}

	npage = ((Form_pg_class) GETSTRUCT(atp))->relpages;
	result = (float64) palloc(sizeof(float64data));
	*result = *temp * npage;
	return result;
}

float64
hashsel(Oid operatorObjectId,
		Oid indrelid,
		AttrNumber attributeNumber,
		char *constValue,
		int32 constFlag,
		int32 nIndexKeys,
		Oid indexrelid)
{

	float64		result;
	float64data resultData;
	HeapTuple	atp;
	int			ntuples;

	if (FunctionalSelectivity(nIndexKeys, attributeNumber))
	{

		/*
		 * Need to call the functions selectivity function here.  For now
		 * simply use 1/Number of Tuples since functions don't currently
		 * have selectivity functions
		 */

		atp = SearchSysCacheTuple(RELOID,
								  ObjectIdGetDatum(indexrelid),
								  0, 0, 0);
		if (!HeapTupleIsValid(atp))
		{
			elog(ERROR, "hashsel: no index tuple %u", indexrelid);
			return 0;
		}
		ntuples = ((Form_pg_class) GETSTRUCT(atp))->reltuples;
		if (ntuples > 0)
			resultData = 1.0 / (float64data) ntuples;
		else
			resultData = (float64data) (1.0 / 100.0);
		result = &resultData;

	}
	else
	{
		RegProcedure oprrest = get_oprrest(operatorObjectId);

		/*
		 * Operators used for indexes should have selectivity estimators.
		 * (An alternative is to default to 0.5, as the optimizer does in
		 * dealing with operators occurring in WHERE clauses, but if you
		 * are going to the trouble of making index support you probably
		 * don't want to miss the benefits of a good selectivity estimate.)
		 */
		if (!oprrest)
			elog(ERROR,
				 "Operator %u must have a restriction selectivity estimator to be used in a hash index",
				 operatorObjectId);

		result = (float64) fmgr(oprrest,
								(char *) operatorObjectId,
								(char *) indrelid,
								(char *) (int) attributeNumber,
								(char *) constValue,
								(char *) constFlag,
								NULL);
	}

	if (!PointerIsValid(result))
		elog(ERROR, "Hash Table Selectivity: bad pointer");
	if (*result < 0.0 || *result > 1.0)
		elog(ERROR, "Hash Table Selectivity: bad value %lf", *result);

	return result;


}

float64
hashnpage(Oid operatorObjectId,
		  Oid indrelid,
		  AttrNumber attributeNumber,
		  char *constValue,
		  int32 constFlag,
		  int32 nIndexKeys,
		  Oid indexrelid)
{
	float64		temp,
				result;
	float64data tempData;
	HeapTuple	atp;
	int			npage;
	int			ntuples;

	atp = SearchSysCacheTuple(RELOID,
							  ObjectIdGetDatum(indexrelid),
							  0, 0, 0);
	if (!HeapTupleIsValid(atp))
	{
		elog(ERROR, "hashsel: no index tuple %u", indexrelid);
		return 0;
	}


	if (FunctionalSelectivity(nIndexKeys, attributeNumber))
	{

		/*
		 * Need to call the functions selectivity function here.  For now,
		 * use 1/Number of Tuples since functions don't currently have
		 * selectivity functions
		 */

		ntuples = ((Form_pg_class) GETSTRUCT(atp))->reltuples;
		if (ntuples > 0)
			tempData = 1.0 / (float64data) ntuples;
		else
			tempData = (float64data) (1.0 / 100.0);
		temp = &tempData;

	}
	else
	{
		RegProcedure oprrest = get_oprrest(operatorObjectId);

		/*
		 * Operators used for indexes should have selectivity estimators.
		 * (An alternative is to default to 0.5, as the optimizer does in
		 * dealing with operators occurring in WHERE clauses, but if you
		 * are going to the trouble of making index support you probably
		 * don't want to miss the benefits of a good selectivity estimate.)
		 */
		if (!oprrest)
			elog(ERROR,
				 "Operator %u must have a restriction selectivity estimator to be used in a hash index",
				 operatorObjectId);

		temp = (float64) fmgr(oprrest,
							  (char *) operatorObjectId,
							  (char *) indrelid,
							  (char *) (int) attributeNumber,
							  (char *) constValue,
							  (char *) constFlag,
							  NULL);
	}

	npage = ((Form_pg_class) GETSTRUCT(atp))->relpages;
	result = (float64) palloc(sizeof(float64data));
	*result = *temp * npage;
	return result;
}


float64
rtsel(Oid operatorObjectId,
	  Oid indrelid,
	  AttrNumber attributeNumber,
	  char *constValue,
	  int32 constFlag,
	  int32 nIndexKeys,
	  Oid indexrelid)
{
	return (btreesel(operatorObjectId, indrelid, attributeNumber,
					 constValue, constFlag, nIndexKeys, indexrelid));
}

float64
rtnpage(Oid operatorObjectId,
		Oid indrelid,
		AttrNumber attributeNumber,
		char *constValue,
		int32 constFlag,
		int32 nIndexKeys,
		Oid indexrelid)
{
	return (btreenpage(operatorObjectId, indrelid, attributeNumber,
					   constValue, constFlag, nIndexKeys, indexrelid));
}

float64
gistsel(Oid operatorObjectId,
		Oid indrelid,
		AttrNumber attributeNumber,
		char *constValue,
		int32 constFlag,
		int32 nIndexKeys,
		Oid indexrelid)
{
	return (btreesel(operatorObjectId, indrelid, attributeNumber,
					 constValue, constFlag, nIndexKeys, indexrelid));
}

float64
gistnpage(Oid operatorObjectId,
		  Oid indrelid,
		  AttrNumber attributeNumber,
		  char *constValue,
		  int32 constFlag,
		  int32 nIndexKeys,
		  Oid indexrelid)
{
	return (btreenpage(operatorObjectId, indrelid, attributeNumber,
					   constValue, constFlag, nIndexKeys, indexrelid));
}