[GitHub] [hive] pvary commented on a diff in pull request #3251: HIVE-26183: Create delete writer for the UPDATE statements

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

pvary commented on code in PR #3251:
URL: https://github.com/apache/hive/pull/3251#discussion_r862623571


##########
iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/hive/HiveIcebergBufferedDeleteWriter.java:
##########
@@ -0,0 +1,172 @@
+/*
+ * 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.mr.hive;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Map;
+import java.util.TreeSet;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.io.Writable;
+import org.apache.iceberg.DeleteFile;
+import org.apache.iceberg.FileFormat;
+import org.apache.iceberg.MetadataColumns;
+import org.apache.iceberg.PartitionKey;
+import org.apache.iceberg.PartitionSpec;
+import org.apache.iceberg.Schema;
+import org.apache.iceberg.data.GenericRecord;
+import org.apache.iceberg.data.InternalRecordWrapper;
+import org.apache.iceberg.data.Record;
+import org.apache.iceberg.deletes.PositionDelete;
+import org.apache.iceberg.io.ClusteredPositionDeleteWriter;
+import org.apache.iceberg.io.DeleteWriteResult;
+import org.apache.iceberg.io.FileIO;
+import org.apache.iceberg.io.FileWriterFactory;
+import org.apache.iceberg.io.OutputFileFactory;
+import org.apache.iceberg.io.PartitioningWriter;
+import org.apache.iceberg.mr.mapred.Container;
+import org.apache.iceberg.relocated.com.google.common.collect.Maps;
+import org.apache.iceberg.relocated.com.google.common.util.concurrent.ThreadFactoryBuilder;
+import org.apache.iceberg.util.Tasks;
+import org.roaringbitmap.longlong.Roaring64Bitmap;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The {@link HiveIcebergBufferedDeleteWriter} needs to handle out of order records.
+ * We need to keep the incoming records in memory until they are written out. To keep the memory consumption minimal
+ * we only write out {@link PositionDelete} files where the row data is omitted, so only the filenames and the rowIds
+ * have to be in the memory.
+ */
+public class HiveIcebergBufferedDeleteWriter implements HiveIcebergWriter {
+  private static final Logger LOG = LoggerFactory.getLogger(HiveIcebergBufferedDeleteWriter.class);
+
+  private static final String DELETE_FILE_THREAD_POOL_SIZE = "iceberg.delete.file.thread.pool.size";
+  private static final int DELETE_FILE_THREAD_POOL_SIZE_DEFAULT = 10;
+
+  // Storing deleted data in a map Partition -> FileName -> BitMap
+  private final Map<PartitionKey, Map<String, Roaring64Bitmap>> buffer = Maps.newHashMap();
+  private final Map<Integer, PartitionSpec> specs;
+  private final Map<PartitionKey, PartitionSpec> keyToSpec = Maps.newHashMap();
+  private final FileFormat format;
+  private final FileWriterFactory<Record> writerFactory;
+  private final OutputFileFactory fileFactory;
+  private final FileIO io;
+  private final long targetFileSize;
+  private final Configuration configuration;
+  private final Record record;
+  private final InternalRecordWrapper wrapper;
+  private FilesForCommit filesForCommit;
+
+  HiveIcebergBufferedDeleteWriter(Schema schema, Map<Integer, PartitionSpec> specs, FileFormat format,
+      FileWriterFactory<Record> writerFactory, OutputFileFactory fileFactory, FileIO io, long targetFileSize,
+      Configuration configuration) {
+    this.specs = specs;
+    this.format = format;
+    this.writerFactory = writerFactory;
+    this.fileFactory = fileFactory;
+    this.io = io;
+    this.targetFileSize = targetFileSize;
+    this.configuration = configuration;
+    this.wrapper = new InternalRecordWrapper(schema.asStruct());
+    this.record = GenericRecord.create(schema);
+  }
+
+  @Override
+  public void write(Writable row) throws IOException {
+    Record rec = ((Container<Record>) row).get();
+    IcebergAcidUtil.getOriginalFromUpdatedRecord(rec, record);
+    String filePath = (String) rec.getField(MetadataColumns.FILE_PATH.name());
+    int specId = IcebergAcidUtil.parseSpecId(rec);
+
+    Map<String, Roaring64Bitmap> deleteMap =
+        buffer.computeIfAbsent(partition(record, specId), key -> {
+          keyToSpec.put(key, specs.get(specId));
+          return Maps.newHashMap();
+        });
+    Roaring64Bitmap deletes = deleteMap.computeIfAbsent(filePath, unused -> new Roaring64Bitmap());
+    deletes.add((Long) rec.getField(MetadataColumns.ROW_POSITION.name()));
+  }
+
+  @Override
+  public void close(boolean abort) throws IOException {
+    long startTime = System.currentTimeMillis();
+    Collection<DeleteFile> deleteFiles = new ConcurrentLinkedQueue<>();
+    if (!abort) {
+      LOG.info("Delete file flush is started");
+      Tasks.foreach(buffer.keySet())
+          .retry(3)
+          .executeWith(fileExecutor(configuration, buffer.size()))
+          .onFailure((partition, exception) -> LOG.debug("Failed to write delete file {}", partition, exception))
+          .run(partition -> {
+            PositionDelete<Record> positionDelete = PositionDelete.create();
+            PartitioningWriter writerForData =
+                new ClusteredPositionDeleteWriter<>(writerFactory, fileFactory, io, format, targetFileSize);
+            try (PartitioningWriter writer = writerForData) {
+              writerForData = writer;

Review Comment:
   So I can use the `AutoCloseable` interface to close the writer, and still get the results after closing the writer. The alternative was:
   ```
   PartitioningWriter writerForData =...
   try {
   [..]
   } finally {
     writerForData.close();
   }
   Files files = writerForData.files();
   ```
   
   What do you think? Which one is easier to read?



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