com.hazelcast.org.apache.calcite.rel.rules.MultiJoinProjectTransposeRule Maven / Gradle / Ivy
/*
* 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 com.hazelcast.com.liance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.com.hazelcast.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 com.hazelcast.org.apache.calcite.rel.rules;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleOperand;
import com.hazelcast.org.apache.calcite.plan.RelOptUtil;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.core.Project;
import com.hazelcast.org.apache.calcite.rel.core.RelFactories;
import com.hazelcast.org.apache.calcite.rel.logical.LogicalJoin;
import com.hazelcast.org.apache.calcite.rel.logical.LogicalProject;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;
/**
* MultiJoinProjectTransposeRule implements the rule for pulling
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalProject}s that are on top of a
* {@link MultiJoin} and beneath a
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalJoin} so the
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalProject} appears above the
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalJoin}.
*
* In the process of doing
* so, also save away information about the respective fields that are
* referenced in the expressions in the
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalProject} we're pulling up, as
* well as the join condition, in the resultant {@link MultiJoin}s
*
*
For example, if we have the following sub-query:
*
*
* (select X.x1, Y.y1 from X, Y
* where X.x2 = Y.y2 and X.x3 = 1 and Y.y3 = 2)
*
* The {@link MultiJoin} associated with (X, Y) associates x1 with X and
* y1 with Y. Although x3 and y3 need to be read due to the filters, they are
* not required after the row scan has com.hazelcast.com.leted and therefore are not saved.
* The join fields, x2 and y2, are also tracked separately.
*
*
Note that by only pulling up projects that are on top of
* {@link MultiJoin}s, we preserve projections on top of row scans.
*
*
See the superclass for details on restrictions regarding which
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalProject}s cannot be pulled.
*/
public class MultiJoinProjectTransposeRule extends JoinProjectTransposeRule {
//~ Static fields/initializers ---------------------------------------------
public static final MultiJoinProjectTransposeRule MULTI_BOTH_PROJECT =
new MultiJoinProjectTransposeRule(
operand(LogicalJoin.class,
operand(LogicalProject.class,
operand(MultiJoin.class, any())),
operand(LogicalProject.class,
operand(MultiJoin.class, any()))),
RelFactories.LOGICAL_BUILDER,
"MultiJoinProjectTransposeRule: with two LogicalProject children");
public static final MultiJoinProjectTransposeRule MULTI_LEFT_PROJECT =
new MultiJoinProjectTransposeRule(
operand(LogicalJoin.class,
some(
operand(LogicalProject.class,
operand(MultiJoin.class, any())))),
RelFactories.LOGICAL_BUILDER,
"MultiJoinProjectTransposeRule: with LogicalProject on left");
public static final MultiJoinProjectTransposeRule MULTI_RIGHT_PROJECT =
new MultiJoinProjectTransposeRule(
operand(LogicalJoin.class,
operand(RelNode.class, any()),
operand(LogicalProject.class,
operand(MultiJoin.class, any()))),
RelFactories.LOGICAL_BUILDER,
"MultiJoinProjectTransposeRule: with LogicalProject on right");
//~ Constructors -----------------------------------------------------------
@Deprecated // to be removed before 2.0
public MultiJoinProjectTransposeRule(
RelOptRuleOperand operand,
String description) {
this(operand, RelFactories.LOGICAL_BUILDER, description);
}
/** Creates a MultiJoinProjectTransposeRule. */
public MultiJoinProjectTransposeRule(
RelOptRuleOperand operand,
RelBuilderFactory relBuilderFactory,
String description) {
super(operand, description, false, relBuilderFactory);
}
//~ Methods ----------------------------------------------------------------
@Override protected boolean hasLeftChild(RelOptRuleCall call) {
return call.rels.length != 4;
}
@Override protected boolean hasRightChild(RelOptRuleCall call) {
return call.rels.length > 3;
}
@Override protected Project getRightChild(RelOptRuleCall call) {
if (call.rels.length == 4) {
return call.rel(2);
} else {
return call.rel(3);
}
}
@Override protected RelNode getProjectChild(
RelOptRuleCall call,
Project project,
boolean leftChild) {
// locate the appropriate MultiJoin based on which rule was fired
// and which projection we're dealing with
MultiJoin multiJoin;
if (leftChild) {
multiJoin = call.rel(2);
} else if (call.rels.length == 4) {
multiJoin = call.rel(3);
} else {
multiJoin = call.rel(4);
}
// create a new MultiJoin that reflects the columns in the projection
// above the MultiJoin
return RelOptUtil.projectMultiJoin(multiJoin, project);
}
}