Field Detail

• LOG

  private static final org.apache.commons.logging.Log LOG

• pool

  protected final ExecutorService pool

• cConnection

  protected final ClusterConnection cConnection

• conf

  protected final org.apache.hadoop.conf.Configuration conf

• get

  protected final Get get

• tableName

  protected final TableName tableName

• timeBeforeReplicas

  protected final int timeBeforeReplicas

• callTimeout

  private final int callTimeout

• retries

  private final int retries

• rpcControllerFactory

  private final RpcControllerFactory rpcControllerFactory

• rpcRetryingCallerFactory

  private final RpcRetryingCallerFactory rpcRetryingCallerFactory

Constructor Detail

• RpcRetryingCallerWithReadReplicas

  public RpcRetryingCallerWithReadReplicas(RpcControllerFactory rpcControllerFactory,
                                   TableName tableName,
                                   ClusterConnection cConnection,
                                   Get get,
                                   ExecutorService pool,
                                   int retries,
                                   int callTimeout,
                                   int timeBeforeReplicas)

Method Detail

• call

  public Result call()
              throws DoNotRetryIOException,
                     InterruptedIOException,
                     RetriesExhaustedException

  Algo: - we put the query into the execution pool. - after x ms, if we don't have a result, we add the queries for the secondary replicas - we take the first answer - when done, we cancel what's left. Cancelling means: - removing from the pool if the actual call was not started - interrupting the call if it has started Client side, we need to take into account - a call is not executed immediately after being put into the pool - a call is a thread. Let's not multiply the number of thread by the number of replicas. Server side, if we can cancel when it's still in the handler pool, it's much better, as a call can take some i/o.

  Globally, the number of retries, timeout and so on still applies, but it's per replica, not global. We continue until all retries are done, or all timeouts are exceeded.

  Throws:

  DoNotRetryIOException

  InterruptedIOException

  RetriesExhaustedException

• throwEnrichedException

  static void throwEnrichedException(ExecutionException e,
                            int retries)
                              throws RetriesExhaustedException,
                                     DoNotRetryIOException

  Extract the real exception from the ExecutionException, and throws what makes more sense.

  Throws:

  RetriesExhaustedException

  DoNotRetryIOException

• addCallsForReplica

  private void addCallsForReplica(ResultBoundedCompletionService<Result> cs,
                        RegionLocations rl,
                        int min,
                        int max)

  Creates the calls and submit them

  Parameters:

  cs - - the completion service to use for submitting

  rl - - the region locations

  min - - the id of the first replica, inclusive

  max - - the id of the last replica, inclusive.

• getRegionLocations

  static RegionLocations getRegionLocations(boolean useCache,
                                   int replicaId,
                                   ClusterConnection cConnection,
                                   TableName tableName,
                                   byte[] row)
                                     throws RetriesExhaustedException,
                                            DoNotRetryIOException,
                                            InterruptedIOException

  Throws:

  RetriesExhaustedException

  DoNotRetryIOException

  InterruptedIOException