[GitHub] [iceberg] chenjunjiedada commented on a change in pull request #2364: Spark: Add an action to rewrite equality deletes

[GitBox <gi...@apache.org>]

chenjunjiedada commented on a change in pull request #2364:
URL: https://github.com/apache/iceberg/pull/2364#discussion_r679356589



##########
File path: spark/src/main/java/org/apache/iceberg/spark/actions/ConvertEqDeletesStrategy.java
##########
@@ -0,0 +1,176 @@
+/*
+ * 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 java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+import org.apache.iceberg.CombinedScanTask;
+import org.apache.iceberg.DeleteFile;
+import org.apache.iceberg.FileContent;
+import org.apache.iceberg.FileScanTask;
+import org.apache.iceberg.StructLike;
+import org.apache.iceberg.Table;
+import org.apache.iceberg.TableProperties;
+import org.apache.iceberg.actions.RewriteDeleteStrategy;
+import org.apache.iceberg.encryption.EncryptionManager;
+import org.apache.iceberg.io.CloseableIterable;
+import org.apache.iceberg.io.FileIO;
+import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet;
+import org.apache.iceberg.relocated.com.google.common.collect.Lists;
+import org.apache.iceberg.relocated.com.google.common.collect.Sets;
+import org.apache.iceberg.spark.source.EqualityDeleteRewriter;
+import org.apache.iceberg.util.Pair;
+import org.apache.iceberg.util.PropertyUtil;
+import org.apache.iceberg.util.StructLikeWrapper;
+import org.apache.iceberg.util.TableScanUtil;
+import org.apache.spark.api.java.JavaRDD;
+import org.apache.spark.api.java.JavaSparkContext;
+import org.apache.spark.broadcast.Broadcast;
+import org.apache.spark.sql.SparkSession;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ConvertEqDeletesStrategy implements RewriteDeleteStrategy {
+  private static final Logger LOG = LoggerFactory.getLogger(ConvertEqDeletesStrategy.class);
+
+  private final Table table;
+  private long deleteTargetSizeInBytes;
+  private int splitLookback;
+  private long splitOpenFileCost;
+
+  private CloseableIterable<FileScanTask> tasksWithEqDelete;
+  private Iterable<DeleteFile> deletesToReplace;
+  private final JavaSparkContext sparkContext;
+
+  /**
+   * Defines whether to split out the result position deletes by data file names.
+   *
+   * This should be used in EqualityDeleteRewriter.
+   */
+  public static final String SPLIT_POSITION_DELETE = "split-position-delete";
+
+  public ConvertEqDeletesStrategy(SparkSession spark, Table table) {
+    this.table = table;
+    this.sparkContext = JavaSparkContext.fromSparkContext(spark.sparkContext());
+    this.deleteTargetSizeInBytes = PropertyUtil.propertyAsLong(
+        table.properties(),
+        TableProperties.DELETE_TARGET_FILE_SIZE_BYTES,
+        TableProperties.WRITE_TARGET_FILE_SIZE_BYTES_DEFAULT);
+    this.splitLookback = PropertyUtil.propertyAsInt(
+        table.properties(),
+        TableProperties.SPLIT_LOOKBACK,
+        TableProperties.SPLIT_LOOKBACK_DEFAULT);
+    this.splitOpenFileCost = PropertyUtil.propertyAsLong(
+        table.properties(),
+        TableProperties.SPLIT_OPEN_FILE_COST,
+        TableProperties.SPLIT_OPEN_FILE_COST_DEFAULT);
+  }
+
+  @Override
+  public String name() {
+    return "CONVERT-EQUALITY-DELETES";
+  }
+
+  @Override
+  public Table table() {
+    return table;
+  }
+
+  @Override
+  public Iterable<DeleteFile> selectDeletes() {
+    CloseableIterable<FileScanTask> fileScanTasks = null;
+    try {
+      fileScanTasks = table.newScan()
+          .ignoreResiduals()
+          .planFiles();
+    } finally {
+      try {
+        if (fileScanTasks != null) {
+          fileScanTasks.close();
+        }
+      } catch (IOException ioe) {
+        LOG.warn("Failed to close task iterable", ioe);
+      }
+    }
+
+    tasksWithEqDelete = CloseableIterable.filter(fileScanTasks, scan ->
+        scan.deletes().stream().anyMatch(delete -> delete.content().equals(FileContent.EQUALITY_DELETES))
+    );
+
+    Set<DeleteFile> eqDeletes = Sets.newHashSet();
+    tasksWithEqDelete.forEach(task -> {
+      eqDeletes.addAll(task.deletes().stream()
+          .filter(deleteFile -> deleteFile.content().equals(FileContent.EQUALITY_DELETES))
+          .collect(Collectors.toList()));
+    });
+
+    deletesToReplace = eqDeletes;
+
+    return deletesToReplace;
+  }
+
+  @Override
+  public Iterable<DeleteFile> rewriteDeletes() {
+    Map<StructLikeWrapper, Collection<FileScanTask>> groupedTasks =
+        TableScanUtil.groupTasksByPartition(table.spec(), tasksWithEqDelete.iterator());
+
+    // Split and combine tasks under each partition
+    List<Pair<StructLike, CombinedScanTask>> combinedScanTasks = groupedTasks.entrySet().stream()

Review comment:
       I'm updating this PR according to the API changes, the changes of `selectDeletesToRewrite` and `rewriteDeletes` are OK to me. But `Iterable<List<FileScanTask>> planDeleteGroups(Iterable<DeleteFile> deleteFiles);` is a bit wired since it returns groups of `List<FileScanTask>`, while a `FileScanTask` could contains several deletes which don't exist in the `deleteFiles`. So I prefer to return `Iterable<list<DeleteFile>>`. It is worth noting that one data file could have several deletes,  so we could not directly using `FileScanTask` to transfer the deletes. This is slightly different from the date file rewrite.
   
   > And we can get the partition StructLike directly from the list of scan tasks instead of passing it through the task pair in EqualityDeleteRewriter. In this way, we can also enable partial progress for commits.
   
   The scan tasks in a group may belong to different partitions. So unless we group deletes by partition, it needs to know the partition values. 
   
   




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