core/src/main/java/org/apache/calcite/rel/metadata/RelMdPercentageOriginalRows.java - calcite - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to you under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.calcite.rel.metadata;

 import org.apache.calcite.adapter.enumerable.EnumerableInterpreter;
 import org.apache.calcite.plan.RelOptCost;
 import org.apache.calcite.rel.RelNode;
 import org.apache.calcite.rel.core.Aggregate;
 import org.apache.calcite.rel.core.Join;
 import org.apache.calcite.rel.core.Union;

 import com.google.common.collect.ImmutableList;

 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.checkerframework.checker.nullness.qual.PolyNull;

 import java.util.List;

 /**
  * RelMdPercentageOriginalRows supplies a default implementation of
  * {@link RelMetadataQuery#getPercentageOriginalRows} for the standard logical
  * algebra.
  */
 public class RelMdPercentageOriginalRows {
   public static final RelMetadataProvider SOURCE =
       ChainedRelMetadataProvider.of(
           ImmutableList.of(
               ReflectiveRelMetadataProvider.reflectiveSource(
                   new RelMdPercentageOriginalRowsHandler(),
                   BuiltInMetadata.PercentageOriginalRows.Handler.class),
               ReflectiveRelMetadataProvider.reflectiveSource(
                   new RelMdCumulativeCost(),
                   BuiltInMetadata.CumulativeCost.Handler.class),
               ReflectiveRelMetadataProvider.reflectiveSource(
                   new RelMdNonCumulativeCost(),
                   BuiltInMetadata.NonCumulativeCost.Handler.class
               )
           ));

   //~ Methods ----------------------------------------------------------------

   private RelMdPercentageOriginalRows() {}


   public @Nullable Double getPercentageOriginalRows(Aggregate rel, RelMetadataQuery mq) {
     // REVIEW jvs 28-Mar-2006: The assumption here seems to be that
     // aggregation does not apply any filtering, so it does not modify the
     // percentage.  That's very much oversimplified.
     return mq.getPercentageOriginalRows(rel.getInput());
   }

   public Double getPercentageOriginalRows(Union rel, RelMetadataQuery mq) {
     double numerator = 0.0;
     double denominator = 0.0;

     // Ignore rel.isDistinct() because it's the same as an aggregate.

     // REVIEW jvs 28-Mar-2006: The original Broadbase formula was broken.
     // It was multiplying percentage into the numerator term rather than
     // than dividing it out of the denominator term, which would be OK if
     // there weren't summation going on.  Probably the cause of the error
     // was the desire to avoid division by zero, which I don't know how to
     // handle so I punt, meaning we return a totally wrong answer in the
     // case where a huge table has been completely filtered away.

     for (RelNode input : rel.getInputs()) {
       Double rowCount = mq.getRowCount(input);
       if (rowCount == null) {
         continue;
       }
       Double percentage = mq.getPercentageOriginalRows(input);
       if (percentage == null) {
         continue;
       }
       if (percentage != 0.0) {
         denominator += rowCount / percentage;
         numerator += rowCount;
       }
     }

     return quotientForPercentage(numerator, denominator);
   }

   public @Nullable Double getPercentageOriginalRows(Join rel, RelMetadataQuery mq) {
     // Assume any single-table filter conditions have already
     // been pushed down.

     // REVIEW jvs 28-Mar-2006: As with aggregation, this is
     // oversimplified.

     // REVIEW jvs 28-Mar-2006:  need any special casing for SemiJoin?

     Double left = mq.getPercentageOriginalRows(rel.getLeft());
     if (left == null) {
       return null;
     }
     Double right = mq.getPercentageOriginalRows(rel.getRight());
     if (right == null) {
       return null;
     }
     return left * right;
   }

   // Catch-all rule when none of the others apply.
   public @Nullable Double getPercentageOriginalRows(RelNode rel, RelMetadataQuery mq) {
     if (rel.getInputs().size() > 1) {
       // No generic formula available for multiple inputs.
       return null;
     }

     if (rel.getInputs().size() == 0) {
       // Assume no filtering happening at leaf.
       return 1.0;
     }

     RelNode child = rel.getInputs().get(0);

     Double childPercentage = mq.getPercentageOriginalRows(child);
     if (childPercentage == null) {
       return null;
     }

     // Compute product of percentage filtering from this rel (assuming any
     // filtering is the effect of single-table filters) with the percentage
     // filtering performed by the child.
     Double relPercentage =
         quotientForPercentage(mq.getRowCount(rel), mq.getRowCount(child));
     if (relPercentage == null) {
       return null;
     }
     double percent = relPercentage * childPercentage;

     // this check is needed in cases where this method is called on a
     // physical rel
     if ((percent < 0.0) || (percent > 1.0)) {
       return null;
     }
     return relPercentage * childPercentage;
   }

   // Ditto for getNonCumulativeCost
   public @Nullable RelOptCost getCumulativeCost(RelNode rel, RelMetadataQuery mq) {
     RelOptCost cost = mq.getNonCumulativeCost(rel);
     if (cost == null) {
       return null;
     }
     List<RelNode> inputs = rel.getInputs();
     for (RelNode input : inputs) {
       RelOptCost inputCost = mq.getCumulativeCost(input);
       if (inputCost == null) {
         return null;
       }
       cost = cost.plus(inputCost);
     }
     return cost;
   }

   public @Nullable RelOptCost getCumulativeCost(EnumerableInterpreter rel,
       RelMetadataQuery mq) {
     return mq.getNonCumulativeCost(rel);
   }

   // Ditto for getNonCumulativeCost
   public @Nullable RelOptCost getNonCumulativeCost(RelNode rel, RelMetadataQuery mq) {
     return rel.computeSelfCost(rel.getCluster().getPlanner(), mq);
   }

   private static @PolyNull Double quotientForPercentage(
       @PolyNull Double numerator,
       @PolyNull Double denominator) {
     if ((numerator == null) || (denominator == null)) {
       return null;
     }

     // may need epsilon instead
     if (denominator == 0.0) {
       // cap at 100%
       return 1.0;
     } else {
       return numerator / denominator;
     }
   }

   /**
    * Binds {@link RelMdPercentageOriginalRows} to {@link BuiltInMetadata.CumulativeCost}.
    */
   private static final class RelMdCumulativeCost
       extends RelMdPercentageOriginalRows
       implements MetadataHandler<BuiltInMetadata.CumulativeCost> {
     @Deprecated // to be removed before 2.0
     @Override public MetadataDef<BuiltInMetadata.CumulativeCost> getDef() {
       return BuiltInMetadata.CumulativeCost.DEF;
     }
   }

   /**
    * Binds {@link RelMdPercentageOriginalRows} to {@link BuiltInMetadata.NonCumulativeCost}.
    */
   private static final class RelMdNonCumulativeCost
       extends RelMdPercentageOriginalRows
       implements MetadataHandler<BuiltInMetadata.NonCumulativeCost> {

     @Deprecated // to be removed before 2.0
     @Override public MetadataDef<BuiltInMetadata.NonCumulativeCost> getDef() {
       return BuiltInMetadata.NonCumulativeCost.DEF;
     }
   }

   /**
    * Binds {@link RelMdPercentageOriginalRows} to {@link BuiltInMetadata.PercentageOriginalRows}.
    */
   private static final class RelMdPercentageOriginalRowsHandler
       extends RelMdPercentageOriginalRows
       implements MetadataHandler<BuiltInMetadata.PercentageOriginalRows> {
     @Deprecated // to be removed before 2.0
     @Override public MetadataDef<BuiltInMetadata.PercentageOriginalRows> getDef() {
       return BuiltInMetadata.PercentageOriginalRows.DEF;
     }
   }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to you under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.calcite.rel.metadata;

	import org.apache.calcite.adapter.enumerable.EnumerableInterpreter;
	import org.apache.calcite.plan.RelOptCost;
	import org.apache.calcite.rel.RelNode;
	import org.apache.calcite.rel.core.Aggregate;
	import org.apache.calcite.rel.core.Join;
	import org.apache.calcite.rel.core.Union;

	import com.google.common.collect.ImmutableList;

	import org.checkerframework.checker.nullness.qual.Nullable;
	import org.checkerframework.checker.nullness.qual.PolyNull;

	import java.util.List;

	/**
	* RelMdPercentageOriginalRows supplies a default implementation of
	* {@link RelMetadataQuery#getPercentageOriginalRows} for the standard logical
	* algebra.
	*/
	public class RelMdPercentageOriginalRows {
	public static final RelMetadataProvider SOURCE =
	ChainedRelMetadataProvider.of(
	ImmutableList.of(
	ReflectiveRelMetadataProvider.reflectiveSource(
	new RelMdPercentageOriginalRowsHandler(),
	BuiltInMetadata.PercentageOriginalRows.Handler.class),
	ReflectiveRelMetadataProvider.reflectiveSource(
	new RelMdCumulativeCost(),
	BuiltInMetadata.CumulativeCost.Handler.class),
	ReflectiveRelMetadataProvider.reflectiveSource(
	new RelMdNonCumulativeCost(),
	BuiltInMetadata.NonCumulativeCost.Handler.class
	)
	));

	//~ Methods ----------------------------------------------------------------

	private RelMdPercentageOriginalRows() {}


	public @Nullable Double getPercentageOriginalRows(Aggregate rel, RelMetadataQuery mq) {
	// REVIEW jvs 28-Mar-2006: The assumption here seems to be that
	// aggregation does not apply any filtering, so it does not modify the
	// percentage. That's very much oversimplified.
	return mq.getPercentageOriginalRows(rel.getInput());
	}

	public Double getPercentageOriginalRows(Union rel, RelMetadataQuery mq) {
	double numerator = 0.0;
	double denominator = 0.0;

	// Ignore rel.isDistinct() because it's the same as an aggregate.

	// REVIEW jvs 28-Mar-2006: The original Broadbase formula was broken.
	// It was multiplying percentage into the numerator term rather than
	// than dividing it out of the denominator term, which would be OK if
	// there weren't summation going on. Probably the cause of the error
	// was the desire to avoid division by zero, which I don't know how to
	// handle so I punt, meaning we return a totally wrong answer in the
	// case where a huge table has been completely filtered away.

	for (RelNode input : rel.getInputs()) {
	Double rowCount = mq.getRowCount(input);
	if (rowCount == null) {
	continue;
	}
	Double percentage = mq.getPercentageOriginalRows(input);
	if (percentage == null) {
	continue;
	}
	if (percentage != 0.0) {
	denominator += rowCount / percentage;
	numerator += rowCount;
	}
	}

	return quotientForPercentage(numerator, denominator);
	}

	public @Nullable Double getPercentageOriginalRows(Join rel, RelMetadataQuery mq) {
	// Assume any single-table filter conditions have already
	// been pushed down.

	// REVIEW jvs 28-Mar-2006: As with aggregation, this is
	// oversimplified.

	// REVIEW jvs 28-Mar-2006: need any special casing for SemiJoin?

	Double left = mq.getPercentageOriginalRows(rel.getLeft());
	if (left == null) {
	return null;
	}
	Double right = mq.getPercentageOriginalRows(rel.getRight());
	if (right == null) {
	return null;
	}
	return left * right;
	}

	// Catch-all rule when none of the others apply.
	public @Nullable Double getPercentageOriginalRows(RelNode rel, RelMetadataQuery mq) {
	if (rel.getInputs().size() > 1) {
	// No generic formula available for multiple inputs.
	return null;
	}

	if (rel.getInputs().size() == 0) {
	// Assume no filtering happening at leaf.
	return 1.0;
	}

	RelNode child = rel.getInputs().get(0);

	Double childPercentage = mq.getPercentageOriginalRows(child);
	if (childPercentage == null) {
	return null;
	}

	// Compute product of percentage filtering from this rel (assuming any
	// filtering is the effect of single-table filters) with the percentage
	// filtering performed by the child.
	Double relPercentage =
	quotientForPercentage(mq.getRowCount(rel), mq.getRowCount(child));
	if (relPercentage == null) {
	return null;
	}
	double percent = relPercentage * childPercentage;

	// this check is needed in cases where this method is called on a
	// physical rel
	if ((percent < 0.0) \|\| (percent > 1.0)) {
	return null;
	}
	return relPercentage * childPercentage;
	}

	// Ditto for getNonCumulativeCost
	public @Nullable RelOptCost getCumulativeCost(RelNode rel, RelMetadataQuery mq) {
	RelOptCost cost = mq.getNonCumulativeCost(rel);
	if (cost == null) {
	return null;
	}
	List<RelNode> inputs = rel.getInputs();
	for (RelNode input : inputs) {
	RelOptCost inputCost = mq.getCumulativeCost(input);
	if (inputCost == null) {
	return null;
	}
	cost = cost.plus(inputCost);
	}
	return cost;
	}

	public @Nullable RelOptCost getCumulativeCost(EnumerableInterpreter rel,
	RelMetadataQuery mq) {
	return mq.getNonCumulativeCost(rel);
	}

	// Ditto for getNonCumulativeCost
	public @Nullable RelOptCost getNonCumulativeCost(RelNode rel, RelMetadataQuery mq) {
	return rel.computeSelfCost(rel.getCluster().getPlanner(), mq);
	}

	private static @PolyNull Double quotientForPercentage(
	@PolyNull Double numerator,
	@PolyNull Double denominator) {
	if ((numerator == null) \|\| (denominator == null)) {
	return null;
	}

	// may need epsilon instead
	if (denominator == 0.0) {
	// cap at 100%
	return 1.0;
	} else {
	return numerator / denominator;
	}
	}

	/**
	* Binds {@link RelMdPercentageOriginalRows} to {@link BuiltInMetadata.CumulativeCost}.
	*/
	private static final class RelMdCumulativeCost
	extends RelMdPercentageOriginalRows
	implements MetadataHandler<BuiltInMetadata.CumulativeCost> {
	@Deprecated // to be removed before 2.0
	@Override public MetadataDef<BuiltInMetadata.CumulativeCost> getDef() {
	return BuiltInMetadata.CumulativeCost.DEF;
	}
	}

	/**
	* Binds {@link RelMdPercentageOriginalRows} to {@link BuiltInMetadata.NonCumulativeCost}.
	*/
	private static final class RelMdNonCumulativeCost
	extends RelMdPercentageOriginalRows
	implements MetadataHandler<BuiltInMetadata.NonCumulativeCost> {

	@Deprecated // to be removed before 2.0
	@Override public MetadataDef<BuiltInMetadata.NonCumulativeCost> getDef() {
	return BuiltInMetadata.NonCumulativeCost.DEF;
	}
	}

	/**
	* Binds {@link RelMdPercentageOriginalRows} to {@link BuiltInMetadata.PercentageOriginalRows}.
	*/
	private static final class RelMdPercentageOriginalRowsHandler
	extends RelMdPercentageOriginalRows
	implements MetadataHandler<BuiltInMetadata.PercentageOriginalRows> {
	@Deprecated // to be removed before 2.0
	@Override public MetadataDef<BuiltInMetadata.PercentageOriginalRows> getDef() {
	return BuiltInMetadata.PercentageOriginalRows.DEF;
	}
	}
	}