/**
* 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.drill.exec.planner.physical;
import java.util.Iterator;
import java.util.List;
import org.apache.drill.common.exceptions.UserException;
import org.apache.drill.common.expression.FieldReference;
import org.apache.drill.common.logical.data.JoinCondition;
import org.apache.drill.exec.physical.impl.join.JoinUtils;
import org.apache.drill.exec.planner.common.DrillJoinRelBase;
import org.apache.drill.exec.planner.physical.visitor.PrelVisitor;
import org.apache.calcite.rel.InvalidRelException;
import org.apache.calcite.rel.core.JoinRelType;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelOptUtil;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeField;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.rex.RexUtil;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.util.Pair;
import com.google.common.collect.Lists;
/**
*
* Base class for MergeJoinPrel and HashJoinPrel
*
*/
public abstract class JoinPrel extends DrillJoinRelBase implements Prel{
private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(JoinPrel.class);
protected JoinUtils.JoinCategory joincategory;
public JoinPrel(RelOptCluster cluster, RelTraitSet traits, RelNode left, RelNode right, RexNode condition,
JoinRelType joinType) throws InvalidRelException{
super(cluster, traits, left, right, condition, joinType);
}
@Override
public <T, X, E extends Throwable> T accept(PrelVisitor<T, X, E> logicalVisitor, X value) throws E {
return logicalVisitor.visitJoin(this, value);
}
@Override
public Iterator<Prel> iterator() {
return PrelUtil.iter(getLeft(), getRight());
}
/**
* Check to make sure that the fields of the inputs are the same as the output field names. If not, insert a project renaming them.
* @param implementor
* @param i
* @param offset
* @param input
* @return
*/
public RelNode getJoinInput(int offset, RelNode input) {
assert uniqueFieldNames(input.getRowType());
final List<String> fields = getRowType().getFieldNames();
final List<String> inputFields = input.getRowType().getFieldNames();
final List<String> outputFields = fields.subList(offset, offset + inputFields.size());
if (!outputFields.equals(inputFields)) {
// Ensure that input field names are the same as output field names.
// If there are duplicate field names on left and right, fields will get
// lost.
// In such case, we need insert a rename Project on top of the input.
return rename(input, input.getRowType().getFieldList(), outputFields);
} else {
return input;
}
}
private RelNode rename(RelNode input, List<RelDataTypeField> inputFields, List<String> outputFieldNames) {
List<RexNode> exprs = Lists.newArrayList();
for (RelDataTypeField field : inputFields) {
RexNode expr = input.getCluster().getRexBuilder().makeInputRef(field.getType(), field.getIndex());
exprs.add(expr);
}
RelDataType rowType = RexUtil.createStructType(input.getCluster().getTypeFactory(), exprs, outputFieldNames);
ProjectPrel proj = new ProjectPrel(input.getCluster(), input.getTraitSet(), input, exprs, rowType);
return proj;
}
@Override
public boolean needsFinalColumnReordering() {
return true;
}
/**
* Build the list of join conditions for this join.
* A join condition is built only for equality and IS NOT DISTINCT FROM comparisons. The difference is:
* null == null is FALSE whereas null IS NOT DISTINCT FROM null is TRUE
* For a use case of the IS NOT DISTINCT FROM comparison, see
* {@link org.apache.calcite.rel.rules.RemoveDistinctAggregateRule}
* @param conditions populated list of join conditions
* @param leftFields join fields from the left input
* @param rightFields join fields from the right input
*/
protected void buildJoinConditions(List<JoinCondition> conditions,
List<String> leftFields,
List<String> rightFields,
List<Integer> leftKeys,
List<Integer> rightKeys) {
List<RexNode> conjuncts = RelOptUtil.conjunctions(this.getCondition());
short i=0;
for (Pair<Integer, Integer> pair : Pair.zip(leftKeys, rightKeys)) {
final RexNode conditionExpr = conjuncts.get(i++);
final SqlKind kind = conditionExpr.getKind();
if (kind != SqlKind.EQUALS && kind != SqlKind.IS_NOT_DISTINCT_FROM) {
throw UserException.unsupportedError()
.message("Unsupported comparator in join condition %s", conditionExpr)
.build(logger);
}
conditions.add(new JoinCondition(kind.toString(),
FieldReference.getWithQuotedRef(leftFields.get(pair.left)),
FieldReference.getWithQuotedRef(rightFields.get(pair.right))));
}
}
}