Airblader commented on a change in pull request #17011: URL: https://github.com/apache/flink/pull/17011#discussion_r697805051
########## File path: flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/plan/rules/physical/stream/PushFilterPastChangelogNormalizeRule.java ########## @@ -0,0 +1,240 @@ +/* + * 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.flink.table.planner.plan.rules.physical.stream; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.table.planner.plan.nodes.physical.stream.StreamPhysicalCalc; +import org.apache.flink.table.planner.plan.nodes.physical.stream.StreamPhysicalChangelogNormalize; + +import org.apache.calcite.plan.RelOptRule; +import org.apache.calcite.plan.RelOptRuleCall; +import org.apache.calcite.plan.RelOptUtil; +import org.apache.calcite.plan.RelRule; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rex.RexLocalRef; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.rex.RexProgram; +import org.apache.calcite.rex.RexProgramBuilder; +import org.apache.calcite.rex.RexUtil; +import org.apache.calcite.tools.RelBuilder; +import org.apache.calcite.util.Pair; + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.List; +import java.util.Set; +import java.util.stream.Collectors; +import java.util.stream.IntStream; + +import static org.apache.flink.table.planner.plan.utils.RexNodeExtractor.extractRefInputFields; + +/** + * Pushes primary key filters through a {@link StreamPhysicalChangelogNormalize ChangelogNormalize} + * operator to reduce its state size. + * + * <p>This rule looks for Calc → ChangelogNormalize where the {@link StreamPhysicalCalc Calc} + * contains a filter condition. The condition is transformed into CNF and then each conjunction is + * tested for whether it affects only primary key columns. If such conditions exist, they are moved + * into a new, separate Calc and pushed through the ChangelogNormalize operator. ChangelogNormalize + * keeps state for every unique key it encounters, thus pushing filters on the primary key in front + * of it helps reduce the size of its state. + * + * <p>Note that pushing primary key filters is safe to do, but pushing any other filters would lead Review comment: Wonky sentence here. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
