org.apache.druid.data.input.SegmentsSplitHintSpec Maven / Gradle / Ivy

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A module that is everything required to understands Druid Segments
There is a newer version: 31.0.0
/*
 * 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 org.apache.druid.java.util.common.HumanReadableBytes;

import javax.annotation.Nullable;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
import java.util.function.Function;

/**
 * {@link SplitHintSpec} for IngestSegmentFirehoseFactory and DruidInputSource.
 *
 * In DruidInputSource, this spec is converted into {@link MaxSizeSplitHintSpec}. As a result, its {@link #split}
 * method is never called (IngestSegmentFirehoseFactory creates splits on its own instead of calling the
 * {@code split()} method). This doesn't necessarily mean this class is deprecated in favor of the MaxSizeSplitHintSpec.
 * We may want to create more optimized splits in the future. For example, segments can be split to maximize the rollup
 * ratio if the segments have different sets of columns or even different value ranges of columns.
 */
public class SegmentsSplitHintSpec implements SplitHintSpec
{
  @SuppressWarnings("unused")
  public static final String TYPE = "segments";

  private static final HumanReadableBytes DEFAULT_MAX_INPUT_SEGMENT_BYTES_PER_TASK = new HumanReadableBytes("1GiB");
  private static final int DEFAULT_MAX_NUM_SEGMENTS = 1000;

  /**
   * Maximum number of bytes of input segments to process in a single task.
   * If a single segment is larger than this number, it will be processed by itself in a single task.
   */
  private final HumanReadableBytes maxInputSegmentBytesPerTask;
  private final int maxNumSegments;

  @JsonCreator
  public SegmentsSplitHintSpec(
      @JsonProperty("maxInputSegmentBytesPerTask") @Nullable HumanReadableBytes maxInputSegmentBytesPerTask,
      @JsonProperty("maxNumSegments") @Nullable Integer maxNumSegments
  )
  {
    this.maxInputSegmentBytesPerTask = maxInputSegmentBytesPerTask == null
                                       ? DEFAULT_MAX_INPUT_SEGMENT_BYTES_PER_TASK
                                       : maxInputSegmentBytesPerTask;
    this.maxNumSegments = maxNumSegments == null ? DEFAULT_MAX_NUM_SEGMENTS : maxNumSegments;
  }

  @JsonProperty
  public HumanReadableBytes getMaxInputSegmentBytesPerTask()
  {
    return maxInputSegmentBytesPerTask;
  }

  @JsonProperty
  public int getMaxNumSegments()
  {
    return maxNumSegments;
  }

  @Override
  public  Iterator> split(Iterator inputIterator, Function inputAttributeExtractor)
  {
    // This method is not supported currently, but we may want to implement in the future to create optimized splits.
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean equals(Object o)
  {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    SegmentsSplitHintSpec that = (SegmentsSplitHintSpec) o;
    return maxNumSegments == that.maxNumSegments &&
           Objects.equals(maxInputSegmentBytesPerTask, that.maxInputSegmentBytesPerTask);
  }

  @Override
  public int hashCode()
  {
    return Objects.hash(maxInputSegmentBytesPerTask, maxNumSegments);
  }

  @Override
  public String toString()
  {
    return "SegmentsSplitHintSpec{" +
           "maxInputSegmentBytesPerTask=" + maxInputSegmentBytesPerTask +
           ", maxNumSegments=" + maxNumSegments +
           '}';
  }
}