org.apache.drill.exec.planner.common.DrillRelOptUtil.java Source code

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Here is the source code for org.apache.drill.exec.planner.common.DrillRelOptUtil.java

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/**
 * 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.common;

import java.util.AbstractList;
import java.util.List;

import com.google.common.collect.Lists;
import org.apache.calcite.plan.RelOptUtil;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.logical.LogicalCalc;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeField;
import org.apache.calcite.rex.RexInputRef;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.sql.type.SqlTypeName;
import org.apache.calcite.util.Pair;
import org.apache.drill.common.types.TypeProtos;
import org.apache.drill.common.types.Types;
import org.apache.drill.exec.resolver.TypeCastRules;

/**
 * Utility class that is a subset of the RelOptUtil class and is a placeholder for Drill specific
 * static methods that are needed during either logical or physical planning.
 */
public abstract class DrillRelOptUtil {

    // Similar to RelOptUtil.areRowTypesEqual() with the additional check for allowSubstring
    public static boolean areRowTypesCompatible(RelDataType rowType1, RelDataType rowType2, boolean compareNames,
            boolean allowSubstring) {
        if (rowType1 == rowType2) {
            return true;
        }
        if (compareNames) {
            // if types are not identity-equal, then either the names or
            // the types must be different
            return false;
        }
        if (rowType2.getFieldCount() != rowType1.getFieldCount()) {
            return false;
        }
        final List<RelDataTypeField> f1 = rowType1.getFieldList();
        final List<RelDataTypeField> f2 = rowType2.getFieldList();
        for (Pair<RelDataTypeField, RelDataTypeField> pair : Pair.zip(f1, f2)) {
            final RelDataType type1 = pair.left.getType();
            final RelDataType type2 = pair.right.getType();
            // If one of the types is ANY comparison should succeed
            if (type1.getSqlTypeName() == SqlTypeName.ANY || type2.getSqlTypeName() == SqlTypeName.ANY) {
                continue;
            }
            if (type1.getSqlTypeName() != type2.getSqlTypeName()) {
                if (allowSubstring
                        && (type1.getSqlTypeName() == SqlTypeName.CHAR
                                && type2.getSqlTypeName() == SqlTypeName.CHAR)
                        && (type1.getPrecision() <= type2.getPrecision())) {
                    return true;
                }

                // Check if Drill implicit casting can resolve the incompatibility
                List<TypeProtos.MinorType> types = Lists.newArrayListWithCapacity(2);
                types.add(Types.getMinorTypeFromName(type1.getSqlTypeName().getName()));
                types.add(Types.getMinorTypeFromName(type2.getSqlTypeName().getName()));
                if (TypeCastRules.getLeastRestrictiveType(types) != null) {
                    return true;
                }

                return false;
            }
        }
        return true;
    }

    /**
     * Returns a relational expression which has the same fields as the
     * underlying expression, but the fields have different names.
     *
     *
     * @param rel        Relational expression
     * @param fieldNames Field names
     * @return Renamed relational expression
     */
    public static RelNode createRename(RelNode rel, final List<String> fieldNames) {
        final List<RelDataTypeField> fields = rel.getRowType().getFieldList();
        assert fieldNames.size() == fields.size();
        final List<RexNode> refs = new AbstractList<RexNode>() {
            public int size() {
                return fields.size();
            }

            public RexNode get(int index) {
                return RexInputRef.of(index, fields);
            }
        };

        return RelOptUtil.createProject(rel, refs, fieldNames, false);
    }
}