content: /*
   * 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.cassandra.db.compaction;
  
  import org.apache.cassandra.db.ColumnFamilyStore;
  import org.apache.cassandra.db.lifecycle.LifecycleTransaction;
  import org.apache.cassandra.io.sstable.CorruptSSTableException;
  import org.apache.cassandra.io.sstable.format.SSTableFormat.Components;
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  import org.apache.cassandra.io.sstable.metadata.StatsMetadata;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Special compaction task that does not do any compaction, instead it
   * just mutates the level metadata on the sstable and notifies the compaction
   * strategy.
   */
  public class SingleSSTableLCSTask extends AbstractCompactionTask
  {
      private static final Logger logger = LoggerFactory.getLogger(SingleSSTableLCSTask.class);
  
      private final int level;
  
      public SingleSSTableLCSTask(ColumnFamilyStore cfs, LifecycleTransaction txn, int level)
      {
          super(cfs, txn);
          assert txn.originals().size() == 1;
          this.level = level;
      }
  
      protected int getLevel()
      {
          return level;
      }
  
      @Override
      protected void executeInternal(ActiveCompactionsTracker activeCompactions)
      {
          run();
      }
  
      @Override
      protected void runMayThrow()
      {
          SSTableReader sstable = transaction.onlyOne();
          StatsMetadata metadataBefore = sstable.getSSTableMetadata();
          if (level == metadataBefore.sstableLevel)
          {
              logger.info("Not compacting {}, level is already {}", sstable, level);
          }
          else
          {
              try
              {
                  logger.info("Changing level on {} from {} to {}", sstable, metadataBefore.sstableLevel, level);
                  sstable.mutateLevelAndReload(level);
              }
              catch (Throwable t)
              {
                  transaction.abort();
                  throw new CorruptSSTableException(t, sstable.descriptor.fileFor(Components.DATA));
              }
              cfs.getTracker().notifySSTableMetadataChanged(sstable, metadataBefore);
          }
          finishTransaction(sstable);
      }
  
      private void finishTransaction(SSTableReader sstable)
      {
          // we simply cancel the transaction since no sstables are added or removed - we just
          // write a new sstable metadata above and then atomically move the new file on top of the old
          transaction.cancel(sstable);
          transaction.prepareToCommit();
          transaction.commit();
      }
  }
  