amansinha100 commented on a change in pull request #1381: DRILL-6475: Unnest: Null fieldId Pointer. URL: https://github.com/apache/drill/pull/1381#discussion_r203262172
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/planner/physical/visitor/AdjustOperatorsRowTypeVisitor.java ########## @@ -0,0 +1,148 @@ +/* + * 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.visitor; + +import java.util.ArrayList; +import java.util.List; +import com.google.common.base.Preconditions; +import org.apache.calcite.rel.type.RelDataType; +import org.apache.calcite.rel.type.RelDataTypeField; +import org.apache.calcite.rex.RexBuilder; +import org.apache.calcite.rex.RexNode; +import org.apache.drill.exec.planner.physical.JoinPrel; +import org.apache.drill.exec.planner.physical.LateralJoinPrel; +import org.apache.drill.exec.planner.physical.Prel; +import org.apache.calcite.rel.RelNode; + +import com.google.common.collect.Lists; +import org.apache.drill.exec.planner.physical.UnnestPrel; + +/** + * AdjustOperatorsRowTypeVisitor visits corresponding operators' which depending upon their functionality + * adjusts their output row types. The adjusting mechanism is unique to each operator. In case of joins this visitor + * adjusts the field names to make sure that upstream operator only sees that there are unique field names even though + * the children of the join has same field names. Whereas in case of lateral/unnest operators it changes the correlated + * field and also the unnest operator's output row type. + */ +public class AdjustOperatorsRowTypeVisitor extends BasePrelVisitor<Prel, Void, RuntimeException>{ Review comment: One minor comment about this..I think having 'RowType' in the visitor class name is slightly misleading because the visitor for joins column renaming is inserting a project below to do the renaming. Also 'RowType' is a Calcite terminology and it is possible (logically speaking) to implement this without actually using RowType. Perhaps use 'Schema' instead of 'RowType' ? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
