pvary commented on code in PR #6382: URL: https://github.com/apache/iceberg/pull/6382#discussion_r1054570635
########## flink/v1.16/flink/src/main/java/org/apache/iceberg/flink/sink/shuffle/ShuffleOperator.java: ########## @@ -0,0 +1,140 @@ +/* + * 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.iceberg.flink.sink.shuffle; + +import java.io.Serializable; +import java.util.Map; +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.common.state.ListState; +import org.apache.flink.api.common.state.ListStateDescriptor; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.java.functions.KeySelector; +import org.apache.flink.api.java.typeutils.MapTypeInfo; +import org.apache.flink.runtime.operators.coordination.OperatorEvent; +import org.apache.flink.runtime.operators.coordination.OperatorEventGateway; +import org.apache.flink.runtime.operators.coordination.OperatorEventHandler; +import org.apache.flink.runtime.state.StateInitializationContext; +import org.apache.flink.runtime.state.StateSnapshotContext; +import org.apache.flink.streaming.api.operators.AbstractStreamOperator; +import org.apache.flink.streaming.api.operators.OneInputStreamOperator; +import org.apache.flink.streaming.runtime.streamrecord.StreamRecord; +import org.apache.iceberg.relocated.com.google.common.annotations.VisibleForTesting; +import org.apache.iceberg.relocated.com.google.common.collect.Maps; + +/** + * Shuffle operator can help to improve data clustering based on the key. + * + * <p>It collects the data statistics information, sends to coordinator and gets the global data + * distribution weight from coordinator. Then it will ingest the weight into data stream(wrap by a + * class{@link ShuffleRecordWrapper}) and send to partitioner. + */ +@Internal +public class ShuffleOperator<T, K extends Serializable> + extends AbstractStreamOperator<ShuffleRecordWrapper<T, K>> + implements OneInputStreamOperator<T, ShuffleRecordWrapper<T, K>>, OperatorEventHandler { + + private static final long serialVersionUID = 1L; + + private final KeySelector<T, K> keySelector; + // the type of the key to collect data statistics + private final TypeInformation<K> keyType; + private final OperatorEventGateway operatorEventGateway; + // key is generated by applying KeySelector to record + // value is the times key occurs + private transient Map<K, Long> localDataStatisticsMap; Review Comment: Also, I am not sure that we want to seamlessly switch between different implementations. @stevenzwu's table describes the following possibilities in the doc where the strategy is based on the table definition and not on the statistics: ``` Partitioned \ Sorted | Unsorted | Sorted ---------------------| ------------------ | ---------------------------- Unpartitioned | None | Range ---------------------| ------------------ | ---------------------------- Partitioned | BinPacking / Hash | BinPacking if SortOrder only contains partition columns | | Range if SortOder contains non-partition columns ``` I think we can we can reasonably expect that we have enough memory to keep the statistics in a map if BinPacking is used. As for Range partitioning strategy, I would expect that we need to use some kind of Digest statistics. I think it would be a very rare corner case when the possible values are fluctuating so much that we need to change dynamically between the Digest and the Map based statistics. In the meantime we might want to provide a `DataStatisticsFactory` for the `ShuffleOperator` to generate the empty statistics, like this: ``` public interface DataStatisticFactory<K> { DataStatistic<K> newDataStatistic(); TypeInformation type(); } ``` -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
