hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/CSLMImmutableSegment.java

/**
 *
 * 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.hadoop.hbase.regionserver;

import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.hbase.util.ClassSize;

/**
 * CSLMImmutableSegment is an abstract class that extends the API supported by a {@link Segment},
 * and {@link ImmutableSegment}. This immutable segment is working with CellSet with
 * ConcurrentSkipListMap (CSLM) delegatee.
 */
@InterfaceAudience.Private
public class CSLMImmutableSegment extends ImmutableSegment {
  public static final long DEEP_OVERHEAD_CSLM =
      ImmutableSegment.DEEP_OVERHEAD + ClassSize.CONCURRENT_SKIPLISTMAP;

  /**------------------------------------------------------------------------
   * Copy C-tor to be used when new CSLMImmutableSegment is being built from a Mutable one.
   * This C-tor should be used when active MutableSegment is pushed into the compaction
   * pipeline and becomes an ImmutableSegment.
   */
  protected CSLMImmutableSegment(Segment segment, MemStoreSizing memstoreSizing) {
    super(segment);
    // update the segment metadata heap size
    long indexOverhead = -MutableSegment.DEEP_OVERHEAD + DEEP_OVERHEAD_CSLM;
    incMemStoreSize(0, indexOverhead, 0, 0); // CSLM is always on-heap
    if (memstoreSizing != null) {
      memstoreSizing.incMemStoreSize(0, indexOverhead, 0, 0);
    }
  }

  @Override
  protected long indexEntrySize() {
    return ClassSize.CONCURRENT_SKIPLISTMAP_ENTRY;
  }

  @Override protected boolean canBeFlattened() {
    return true;
  }
}