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 java.util.Set;
  import java.util.stream.Collectors;
  
  import org.apache.cassandra.db.ColumnFamilyStore;
  import org.apache.cassandra.db.Directories;
  import org.apache.cassandra.db.compaction.writers.CompactionAwareWriter;
  import org.apache.cassandra.db.compaction.writers.MajorLeveledCompactionWriter;
  import org.apache.cassandra.db.compaction.writers.MaxSSTableSizeWriter;
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  import org.apache.cassandra.db.lifecycle.ILifecycleTransaction;
  
  public class LeveledCompactionTask extends CompactionTask
  {
      private final int level;
      private final long maxSSTableBytes;
      private final boolean majorCompaction;
  
      public LeveledCompactionTask(ColumnFamilyStore cfs, ILifecycleTransaction txn, int level, long gcBefore, long maxSSTableBytes, boolean majorCompaction)
      {
          super(cfs, txn, gcBefore);
          this.level = level;
          this.maxSSTableBytes = maxSSTableBytes;
          this.majorCompaction = majorCompaction;
      }
  
      @Override
      public CompactionAwareWriter getCompactionAwareWriter(ColumnFamilyStore cfs,
                                                            Directories directories,
                                                            ILifecycleTransaction txn,
                                                            Set<SSTableReader> nonExpiredSSTables)
      {
          if (majorCompaction)
              return new MajorLeveledCompactionWriter(cfs, directories, txn, nonExpiredSSTables, maxSSTableBytes, false);
          return new MaxSSTableSizeWriter(cfs, directories, txn, nonExpiredSSTables, maxSSTableBytes, getLevel(), false);
      }
  
      @Override
      protected boolean partialCompactionsAcceptable()
      {
          return level == 0;
      }
  
      protected int getLevel()
      {
          return level;
      }
  
      @Override
      public boolean reduceScopeForLimitedSpace(Set<SSTableReader> nonExpiredSSTables, long expectedSize)
      {
          if (nonExpiredSSTables.size() > 1 && level <= 1)
          {
              // Try again w/o the largest one.
              logger.warn("insufficient space to do L0 -> L{} compaction. {}MiB required, {} for compaction {}",
                          level,
                          (float) expectedSize / 1024 / 1024,
                          transaction.originals()
                                     .stream()
                                     .map(sstable -> String.format("%s (level=%s, size=%s)", sstable, sstable.getSSTableLevel(), sstable.onDiskLength()))
                                     .collect(Collectors.joining(",")),
                          transaction.opId());
              // Note that we have removed files that are still marked as compacting.
              // This suboptimal but ok since the caller will unmark all the sstables at the end.
              int l0SSTableCount = 0;
              SSTableReader largestL0SSTable = null;
              for (SSTableReader sstable : nonExpiredSSTables)
              {
                  if (sstable.getSSTableLevel() == 0)
                  {
                      l0SSTableCount++;
                      if (largestL0SSTable == null || sstable.onDiskLength() > largestL0SSTable.onDiskLength())
                          largestL0SSTable = sstable;
                  }
              }
              // no point doing a L0 -> L{0,1} compaction if we have cancelled all L0 sstables
              if (largestL0SSTable != null && l0SSTableCount > 1)
              {
                  logger.info("Removing {} (level={}, size={}) from compaction {}",
                              largestL0SSTable,
                              largestL0SSTable.getSSTableLevel(),
                              largestL0SSTable.onDiskLength(),
                              transaction.opId());
                  transaction.cancel(largestL0SSTable);
                  nonExpiredSSTables.remove(largestL0SSTable);
                  return true;
              }
          }
          return false;
      }
  }
  