[GitHub] [iceberg] szehon-ho commented on a diff in pull request #7692: Core: Add writer for unordered position deletes

["szehon-ho (via GitHub)" <gi...@apache.org>]

szehon-ho commented on code in PR #7692:
URL: https://github.com/apache/iceberg/pull/7692#discussion_r1204801749


##########
core/src/main/java/org/apache/iceberg/deletes/PositionDelete.java:
##########
@@ -38,6 +38,13 @@ public PositionDelete<R> set(CharSequence newPath, long newPos, R newRow) {
     return this;
   }
 
+  public PositionDelete<R> set(CharSequence newPath, long newPos) {
+    this.path = newPath;

Review Comment:
   Nit question: is it cleaner to have this constructor delegate to the other one?



##########
core/src/main/java/org/apache/iceberg/deletes/SortingPositionOnlyDeleteWriter.java:
##########
@@ -0,0 +1,111 @@
+/*
+ * 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.deletes;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import org.apache.iceberg.io.DeleteWriteResult;
+import org.apache.iceberg.io.FileWriter;
+import org.apache.iceberg.relocated.com.google.common.collect.Lists;
+import org.apache.iceberg.relocated.com.google.common.collect.Maps;
+import org.apache.iceberg.types.Comparators;
+import org.apache.iceberg.util.CharSequenceWrapper;
+import org.roaringbitmap.longlong.PeekableLongIterator;
+import org.roaringbitmap.longlong.Roaring64Bitmap;
+
+/**
+ * A position delete writer that is capable of handling unordered deletes without rows.

Review Comment:
   Nit: can we add javadoc to the PositionDeleteWriter, when we get a chance?



##########
spark/v3.4/spark/src/jmh/java/org/apache/iceberg/spark/source/WritersBenchmark.java:
##########
@@ -93,14 +100,33 @@ public void setupBenchmark() {
             row -> transform.bind(Types.IntegerType.get()).apply(row.getInt(1))));
     this.rows = data;
 
-    this.positionDeleteRows =
-        RandomData.generateSpark(DeleteSchemaUtil.pathPosSchema(), NUM_ROWS, 0L);
+    this.positionDeleteRows = generatePositionDeletes(false /* shuffle */);

Review Comment:
   Don't shuffle?



##########
spark/v3.4/spark/src/jmh/java/org/apache/iceberg/spark/source/WritersBenchmark.java:
##########
@@ -93,14 +100,33 @@ public void setupBenchmark() {
             row -> transform.bind(Types.IntegerType.get()).apply(row.getInt(1))));
     this.rows = data;
 
-    this.positionDeleteRows =
-        RandomData.generateSpark(DeleteSchemaUtil.pathPosSchema(), NUM_ROWS, 0L);
+    this.positionDeleteRows = generatePositionDeletes(false /* shuffle */);
+    this.shuffledPositionDeleteRows = generatePositionDeletes(true /* shuffle */);
 
     this.unpartitionedSpec = table().specs().get(0);
     Preconditions.checkArgument(unpartitionedSpec.isUnpartitioned());
     this.partitionedSpec = table().specs().get(1);
   }
 
+  private Iterable<InternalRow> generatePositionDeletes(boolean shuffle) {
+    int numDeletes = NUM_DATA_FILES_PER_POSITION_DELETE_FILE * NUM_DELETED_POSITIONS_PER_DATA_FILE;
+    List<InternalRow> deletes = Lists.newArrayListWithExpectedSize(numDeletes);
+
+    for (int pathIndex = 0; pathIndex < NUM_DATA_FILES_PER_POSITION_DELETE_FILE; pathIndex++) {
+      UTF8String path = UTF8String.fromString("path/to/position/delete/file/" + UUID.randomUUID());
+      int step = 10;

Review Comment:
   why not just make this outside?



##########
spark/v3.4/spark/src/jmh/java/org/apache/iceberg/spark/source/WritersBenchmark.java:
##########
@@ -363,6 +389,60 @@ public void writeUnpartitionedClusteredPositionDeleteWriter(Blackhole blackhole)
     blackhole.consume(writer);
   }
 
+  @Benchmark
+  @Threads(1)
+  public void writeUnpartitionedFanoutPositionDeleteWriter(Blackhole blackhole) throws IOException {
+    FileIO io = table().io();
+
+    OutputFileFactory fileFactory = newFileFactory();
+    SparkFileWriterFactory writerFactory =
+        SparkFileWriterFactory.builderFor(table()).dataFileFormat(fileFormat()).build();
+
+    FanoutPositionOnlyDeleteWriter<InternalRow> writer =
+        new FanoutPositionOnlyDeleteWriter<>(
+            writerFactory, fileFactory, io, TARGET_FILE_SIZE_IN_BYTES);
+
+    PositionDelete<InternalRow> positionDelete = PositionDelete.create();
+    try (FanoutPositionOnlyDeleteWriter<InternalRow> closeableWriter = writer) {
+      for (InternalRow row : positionDeleteRows) {
+        String path = row.getString(0);
+        long pos = row.getLong(1);
+        positionDelete.set(path, pos, null);
+        closeableWriter.write(positionDelete, unpartitionedSpec, null);
+      }
+    }
+
+    blackhole.consume(writer);
+  }
+
+  @Benchmark
+  @Threads(1)
+  public void writeUnpartitionedFanoutPositionDeleteWriterShuffled(Blackhole blackhole)

Review Comment:
   About memory overhead (not sure any thing measures it now):  Should be just additional space of map (data_file_path => bitmaps)?  Will there be cases, esp in fanout, where a writer writes many delete of many data files, that will start to stress it?



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