wuchong commented on a change in pull request #8109: [FLINK-12017][table-planner-blink] Support translation from Rank/Deduplicate to StreamTransformation URL: https://github.com/apache/flink/pull/8109#discussion_r275105629
########## File path: flink-table/flink-table-runtime-blink/src/main/java/org/apache/flink/table/runtime/deduplicate/DeduplicateFunction.java ########## @@ -0,0 +1,92 @@ +/* + * 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.runtime.deduplicate; + +import org.apache.flink.api.common.state.ValueState; +import org.apache.flink.api.common.state.ValueStateDescriptor; +import org.apache.flink.api.common.typeinfo.Types; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.table.dataformat.BaseRow; +import org.apache.flink.table.runtime.functions.KeyedProcessFunctionWithCleanupState; +import org.apache.flink.table.typeutils.BaseRowTypeInfo; +import org.apache.flink.util.Collector; + +import static org.apache.flink.table.runtime.deduplicate.DeduplicateFunctionHelper.processFirstRow; +import static org.apache.flink.table.runtime.deduplicate.DeduplicateFunctionHelper.processLastRow; + +/** + * This function is used to deduplicate on keys and keeps only first row or last row. + */ +public class DeduplicateFunction + extends KeyedProcessFunctionWithCleanupState<BaseRow, BaseRow, BaseRow> { + + private static final long serialVersionUID = 4950071982706870944L; + + private final BaseRowTypeInfo rowTypeInfo; + private final boolean generateRetraction; + private final boolean keepLastRow; + + // state stores complete row if keep last row and generate retraction is true, + // else stores a flag to indicate whether key appears before. + private ValueState state; + + public DeduplicateFunction(long minRetentionTime, long maxRetentionTime, BaseRowTypeInfo rowTypeInfo, + boolean generateRetraction, boolean keepLastRow) { + super(minRetentionTime, maxRetentionTime); + this.rowTypeInfo = rowTypeInfo; + this.generateRetraction = generateRetraction; + this.keepLastRow = keepLastRow; + } + + @Override + public void open(Configuration configure) throws Exception { + super.open(configure); + String stateName = keepLastRow ? "DeduplicateFunctionKeepLastRow" : "DeduplicateFunctionKeepFirstRow"; + initCleanupTimeState(stateName); + ValueStateDescriptor stateDesc = null; + if (keepLastRow && generateRetraction) { + // if need generate retraction and keep last row, stores complete row into state + stateDesc = new ValueStateDescriptor("deduplicateFunction", rowTypeInfo); + } else { + // else stores a flag to indicator whether pk appears before. + stateDesc = new ValueStateDescriptor("fistValueState", Types.BOOLEAN); Review comment: Actually, I don't like current design of `DeduplicateFunction` and `MiniBatchDeduplicateFunction` which mixes firstRow and lastRow implementation in one class. IMO, they share little things, especially they have different state design. The firstRow only need a `ValueState<Boolean>`, but lastRow need a `ValueState<BaseRow>`. In current implementation, we erased the generic type, which is error-prone. Because we may put a `Boolean` into `ValueState<BaseRow>`. Btw, when `keepLastRow && !generateRetraction` is true, we don't need a state at all, we can simply forward rows. My suggestion is separate the implementation into different functions (FirstRow and LastRow). ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
