zabetak commented on a change in pull request #1020: [CALCITE-2812] Add algebraic operators to allow expressing recursive queries (Ruben Quesada Lopez) URL: https://github.com/apache/calcite/pull/1020#discussion_r258431497
########## File path: core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableDeltaTableScan.java ########## @@ -0,0 +1,67 @@ +/* + * 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.adapter.enumerable; + +import org.apache.calcite.linq4j.tree.BlockBuilder; +import org.apache.calcite.linq4j.tree.Expression; +import org.apache.calcite.linq4j.tree.Expressions; +import org.apache.calcite.plan.RelOptCluster; +import org.apache.calcite.plan.RelOptTable; +import org.apache.calcite.rel.core.TableScan; +import org.apache.calcite.schema.ModifiableTable; +import org.apache.calcite.util.BuiltInMethod; + + +/** + * Implementation of delta table (used to accumulate results in a recursive query) in + * {@link org.apache.calcite.adapter.enumerable.EnumerableConvention enumerable calling convention}. + */ +public class EnumerableDeltaTableScan extends TableScan implements EnumerableRel { Review comment: By looking into the code I don't see something fundamentally different from a regular table scan. Due to this I am less worried about non-expecting rules firing. However, I have the feeling that EnumerableDeltaTableScan and likewise LogicalDeltaTableScan can completely dissapear. LogicalDeltaTableScan can be possibly replaced by a regular LogicalTableScan and EnumerableDeltaTableScan by EnumerableTableScan. The logic of obtaining a table from the context could be part of the Table implementation. ---------------------------------------------------------------- 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
