[GitHub] [druid] jnaous commented on a change in pull request #9360: Create splits of multiple files for parallel indexing

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

jnaous commented on a change in pull request #9360: Create splits of multiple files for parallel indexing
URL: https://github.com/apache/druid/pull/9360#discussion_r382949821
 
 

 ##########
 File path: core/src/main/java/org/apache/druid/data/input/MaxSizeSplitHintSpec.java
 ##########
 @@ -0,0 +1,119 @@
+/*
+ * 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.druid.data.input;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.annotations.VisibleForTesting;
+
+import javax.annotation.Nullable;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Objects;
+import java.util.function.Function;
+
+/**
+ * A SplitHintSpec that can create splits of multiple files.
+ * A split created by this class can have one or more input files.
+ * If there is only one file in the split, its size can be larger than {@link #maxSplitSize}.
+ * If there are two or more files in the split, their total size cannot be larger than {@link #maxSplitSize}.
+ */
+public class MaxSizeSplitHintSpec implements SplitHintSpec
+{
+  public static final String TYPE = "maxSize";
+
+  @VisibleForTesting
+  static final long DEFAULT_MAX_SPLIT_SIZE = 512 * 1024 * 1024;
+
+  private final long maxSplitSize;
+
+  @JsonCreator
+  public MaxSizeSplitHintSpec(@JsonProperty("maxSplitSize") @Nullable Long maxSplitSize)
+  {
+    this.maxSplitSize = maxSplitSize == null ? DEFAULT_MAX_SPLIT_SIZE : maxSplitSize;
+  }
+
+  @JsonProperty
+  public long getMaxSplitSize()
+  {
+    return maxSplitSize;
+  }
+
+  @Override
+  public <T> Iterator<List<T>> split(Iterator<T> inputIterator, Function<T, InputFileAttribute> inputAttributeExtractor)
+  {
+    return new Iterator<List<T>>()
+    {
+      private T peeking;
 
 Review comment:
   I think you can simplify the logic of the next method below if you initialize peeking to inputIterator.next(), and only set peeking to null when inputIterator.hasNext() is false. In your next() below, you would just keeping shifting values from inputIterator into current after each iteration as long as there are more inputs.

----------------------------------------------------------------
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.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For additional commands, e-mail: commits-help@druid.apache.org