001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.client.backoff;
019
020import static org.apache.hadoop.hbase.client.ConnectionUtils.SLEEP_DELTA_NS;
021import static org.apache.hadoop.hbase.client.ConnectionUtils.getPauseTime;
022
023import java.util.OptionalLong;
024import java.util.concurrent.TimeUnit;
025import org.apache.hadoop.hbase.HBaseServerException;
026import org.apache.hadoop.hbase.quotas.RpcThrottlingException;
027import org.apache.yetus.audience.InterfaceAudience;
028import org.slf4j.Logger;
029import org.slf4j.LoggerFactory;
030
031@InterfaceAudience.Private
032public class HBaseServerExceptionPauseManager {
033  private static final Logger LOG = LoggerFactory.getLogger(HBaseServerExceptionPauseManager.class);
034
035  private final long pauseNs;
036  private final long pauseNsForServerOverloaded;
037  private final long timeoutNs;
038
039  public HBaseServerExceptionPauseManager(long pauseNs, long pauseNsForServerOverloaded,
040    long timeoutNs) {
041    this.pauseNs = pauseNs;
042    this.pauseNsForServerOverloaded = pauseNsForServerOverloaded;
043    this.timeoutNs = timeoutNs;
044  }
045
046  /**
047   * Returns the nanos, if any, for which the client should wait
048   * @param error The exception from the server
049   * @param tries The current retry count
050   * @return The time, in nanos, to pause. If empty then pausing would exceed our timeout, so we
051   *         should throw now
052   */
053  public OptionalLong getPauseNsFromException(Throwable error, int tries, long startNs) {
054    long expectedSleepNs;
055    long remainingTimeNs = remainingTimeNs(startNs) - SLEEP_DELTA_NS;
056    if (error instanceof RpcThrottlingException) {
057      RpcThrottlingException rpcThrottlingException = (RpcThrottlingException) error;
058      expectedSleepNs = TimeUnit.MILLISECONDS.toNanos(rpcThrottlingException.getWaitInterval());
059      if (expectedSleepNs > remainingTimeNs && remainingTimeNs > 0) {
060        if (LOG.isDebugEnabled()) {
061          LOG.debug("RpcThrottlingException suggested pause of {}ns which would exceed "
062            + "the timeout. We should throw instead.", expectedSleepNs, rpcThrottlingException);
063        }
064        return OptionalLong.empty();
065      }
066      if (LOG.isDebugEnabled()) {
067        LOG.debug("Sleeping for {}ns after catching RpcThrottlingException", expectedSleepNs,
068          rpcThrottlingException);
069      }
070    } else {
071      expectedSleepNs =
072        HBaseServerException.isServerOverloaded(error) ? pauseNsForServerOverloaded : pauseNs;
073      // RpcThrottlingException tells us exactly how long the client should wait for,
074      // so we should not factor in the retry count for said exception
075      expectedSleepNs = getPauseTime(expectedSleepNs, tries - 1);
076    }
077
078    if (timeoutNs > 0) {
079      if (remainingTimeNs <= 0) {
080        return OptionalLong.empty();
081      }
082      expectedSleepNs = Math.min(remainingTimeNs, expectedSleepNs);
083    }
084
085    return OptionalLong.of(expectedSleepNs);
086  }
087
088  public long remainingTimeNs(long startNs) {
089    return timeoutNs - (System.nanoTime() - startNs);
090  }
091
092}