szehon-ho commented on code in PR #9724: URL: https://github.com/apache/iceberg/pull/9724#discussion_r1724047895
########## spark/v3.5/spark/src/main/java/org/apache/iceberg/spark/actions/RemoveDanglingDeletesSparkAction.java: ########## @@ -0,0 +1,179 @@ +/* + * 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.spark.actions; + +import static org.apache.spark.sql.functions.col; +import static org.apache.spark.sql.functions.min; + +import java.util.Collections; +import java.util.List; +import java.util.stream.Collectors; +import org.apache.iceberg.DataFile; +import org.apache.iceberg.DeleteFile; +import org.apache.iceberg.MetadataTableType; +import org.apache.iceberg.Partitioning; +import org.apache.iceberg.RewriteFiles; +import org.apache.iceberg.Table; +import org.apache.iceberg.actions.ImmutableRemoveDanglingDeleteFiles; +import org.apache.iceberg.actions.RemoveDanglingDeleteFiles; +import org.apache.iceberg.spark.JobGroupInfo; +import org.apache.iceberg.spark.SparkDeleteFile; +import org.apache.iceberg.types.Types; +import org.apache.spark.sql.Column; +import org.apache.spark.sql.Dataset; +import org.apache.spark.sql.Row; +import org.apache.spark.sql.SparkSession; +import org.apache.spark.sql.types.StructType; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * An action that removes dangling delete files from the current snapshot. A delete file is dangling + * if its deletes no longer applies to any live data files. + * + * <p>The following dangling delete files are removed: + * + * <ul> + * <li>Position delete files with a data sequence number less than that of any data file in the + * same partition + * <li>Equality delete files with a data sequence number less than or equal to that of any data + * file in the same partition + * </ul> + */ +class RemoveDanglingDeletesSparkAction + extends BaseSnapshotUpdateSparkAction<RemoveDanglingDeletesSparkAction> + implements RemoveDanglingDeleteFiles { + + private static final Logger LOG = LoggerFactory.getLogger(RemoveDanglingDeletesSparkAction.class); + private final Table table; + + protected RemoveDanglingDeletesSparkAction(SparkSession spark, Table table) { + super(spark.cloneSession()); + this.table = table; + } + + @Override + protected RemoveDanglingDeletesSparkAction self() { + return this; + } + + public Result execute() { + if (table.specs().size() == 1 && table.spec().isUnpartitioned()) { + // ManifestFilterManager already performs this table-wide delete on each commit + return ImmutableRemoveDanglingDeleteFiles.Result.builder() + .removedDeleteFiles(Collections.emptyList()) + .build(); + } + + String desc = String.format("Removing dangling delete in %s", table.name()); + JobGroupInfo info = newJobGroupInfo("REMOVE-DELETES", desc); + return withJobGroupInfo(info, this::doExecute); + } + + Result doExecute() { + RewriteFiles rewriteFiles = table.newRewrite(); + List<DeleteFile> danglingDeletes = findDanglingDeletes(); + for (DeleteFile deleteFile : danglingDeletes) { + LOG.debug("Removing dangling delete file {}", deleteFile.path()); + rewriteFiles.deleteFile(deleteFile); + } + + if (!danglingDeletes.isEmpty()) { + commit(rewriteFiles); + } + + return ImmutableRemoveDanglingDeleteFiles.Result.builder() + .removedDeleteFiles(danglingDeletes) + .build(); + } + + /** + * Dangling delete files can be identified with following steps + * + * <p>1.Group data files by partition keys and find the minimum data sequence number in each + * group. + * + * <p>2. Left outer join delete files with partition-grouped data files on partition keys. + * + * <p>3. Filter results to find dangling delete files by comparing delete file sequence_number to Review Comment: Sorry for making another suggestion, how about: ``` Find dangling deletes by comparing each delete file's sequence number to its partition's minimum data sequence number.``` or ``` Compare each delete file's sequence number to its partition's minimum data sequence number to find dangling deletes.``` Reading 'filter results to find ...' is a bit convoluted -- 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. 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