core/src/main/java/org/apache/accumulo/testing/core/randomwalk/bulk/SelectiveQueueing.java

/*
 * 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.testing.core.randomwalk.bulk;

import java.util.concurrent.ThreadPoolExecutor;

import org.apache.accumulo.core.client.AccumuloClient;
import org.apache.accumulo.testing.core.randomwalk.RandWalkEnv;
import org.apache.accumulo.testing.core.randomwalk.State;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Chooses whether or not an operation should be queued based on the current thread pool queue length and the number of available TServers.
 */
public class SelectiveQueueing {
  private static final Logger log = LoggerFactory.getLogger(SelectiveQueueing.class);

  public static boolean shouldQueueOperation(State state, RandWalkEnv env) throws Exception {
    final ThreadPoolExecutor pool = (ThreadPoolExecutor) state.get("pool");
    long queuedThreads = pool.getTaskCount() - pool.getActiveCount() - pool.getCompletedTaskCount();
    final AccumuloClient client = env.getAccumuloClient();
    int numTservers = client.instanceOperations().getTabletServers().size();

    if (!shouldQueue(queuedThreads, numTservers)) {
      log.info("Not queueing because of " + queuedThreads + " outstanding tasks");
      return false;
    }

    return true;
  }

  private static boolean shouldQueue(long queuedThreads, int numTservers) {
    return queuedThreads < numTservers * 50;
  }
}