org.apache.accumulo.tserver.tablet.MinorCompactionTask Maven / Gradle / Ivy

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The tablet server for Apache Accumulo to host tablets of data tables.
There is a newer version: 3.0.0
/*
 * 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.accumulo.tserver.tablet;

import java.io.IOException;

import org.apache.accumulo.core.metadata.schema.DataFileValue;
import org.apache.accumulo.core.trace.TraceUtil;
import org.apache.accumulo.server.fs.FileRef;
import org.apache.accumulo.tserver.MinorCompactionReason;
import org.apache.accumulo.tserver.compaction.MajorCompactionReason;
import org.apache.htrace.Trace;
import org.apache.htrace.TraceScope;
import org.apache.htrace.impl.ProbabilitySampler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

class MinorCompactionTask implements Runnable {

  private static final Logger log = LoggerFactory.getLogger(MinorCompactionTask.class);

  private final Tablet tablet;
  private long queued;
  private CommitSession commitSession;
  private DataFileValue stats;
  private FileRef mergeFile;
  private long flushId;
  private MinorCompactionReason mincReason;
  private double tracePercent;

  MinorCompactionTask(Tablet tablet, FileRef mergeFile, CommitSession commitSession, long flushId,
      MinorCompactionReason mincReason, double tracePercent) {
    this.tablet = tablet;
    queued = System.currentTimeMillis();
    tablet.minorCompactionWaitingToStart();
    this.commitSession = commitSession;
    this.mergeFile = mergeFile;
    this.flushId = flushId;
    this.mincReason = mincReason;
    this.tracePercent = tracePercent;
  }

  @Override
  public void run() {
    tablet.minorCompactionStarted();
    ProbabilitySampler sampler = TraceUtil.probabilitySampler(tracePercent);
    try {
      try (TraceScope minorCompaction = Trace.startSpan("minorCompaction", sampler)) {
        FileRef newMapfileLocation = tablet.getNextMapFilename(mergeFile == null ? "F" : "M");
        FileRef tmpFileRef = new FileRef(newMapfileLocation.path() + "_tmp");
        try (TraceScope span = Trace.startSpan("waitForCommits")) {
          synchronized (tablet) {
            commitSession.waitForCommitsToFinish();
          }
        }
        try (TraceScope span = Trace.startSpan("start")) {
          while (true) {
            try {
              /*
               * the purpose of the minor compaction start event is to keep track of the filename...
               * in the case where the metadata table write for the minor compaction finishes and
               * the process dies before writing the minor compaction finish event, then the start
               * event+filename in metadata table will prevent recovery of duplicate data... the
               * minor compaction start event could be written at any time before the metadata write
               * for the minor compaction
               */
              tablet.getTabletServer().minorCompactionStarted(commitSession,
                  commitSession.getWALogSeq() + 1, newMapfileLocation.path().toString());
              break;
            } catch (IOException e) {
              log.warn("Failed to write to write ahead log {}", e.getMessage(), e);
            }
          }
        }
        try (TraceScope span = Trace.startSpan("compact")) {
          this.stats = tablet.minorCompact(tablet.getTabletMemory().getMinCMemTable(), tmpFileRef,
              newMapfileLocation, mergeFile, true, queued, commitSession, flushId, mincReason);
        }

        if (minorCompaction.getSpan() != null) {
          minorCompaction.getSpan().addKVAnnotation("extent", tablet.getExtent().toString());
          minorCompaction.getSpan().addKVAnnotation("numEntries",
              Long.toString(this.stats.getNumEntries()));
          minorCompaction.getSpan().addKVAnnotation("size", Long.toString(this.stats.getSize()));
        }
      }

      if (tablet.needsSplit()) {
        tablet.getTabletServer().executeSplit(tablet);
      } else {
        tablet.initiateMajorCompaction(MajorCompactionReason.NORMAL);
      }
    } catch (Throwable t) {
      log.error("Unknown error during minor compaction for extent: " + tablet.getExtent(), t);
      throw new RuntimeException(t);
    } finally {
      tablet.minorCompactionComplete();
    }
  }
}