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From paul-rogers <...@git.apache.org>
Subject [GitHub] drill pull request #928: DRILL-5716: Queue-driven memory allocation
Date Fri, 01 Sep 2017 21:51:03 GMT
Github user paul-rogers commented on a diff in the pull request:

    https://github.com/apache/drill/pull/928#discussion_r136668047
  
    --- Diff: exec/java-exec/src/main/java/org/apache/drill/exec/work/foreman/rm/DistributedQueryQueue.java
---
    @@ -0,0 +1,272 @@
    +/*
    + * 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.drill.exec.work.foreman.rm;
    +
    +import java.util.concurrent.TimeUnit;
    +
    +import javax.xml.bind.annotation.XmlRootElement;
    +
    +import org.apache.drill.exec.ExecConstants;
    +import org.apache.drill.exec.coord.ClusterCoordinator;
    +import org.apache.drill.exec.coord.DistributedSemaphore;
    +import org.apache.drill.exec.coord.DistributedSemaphore.DistributedLease;
    +import org.apache.drill.exec.proto.UserBitShared.QueryId;
    +import org.apache.drill.exec.proto.helper.QueryIdHelper;
    +import org.apache.drill.exec.server.DrillbitContext;
    +import org.apache.drill.exec.server.options.SystemOptionManager;
    +
    +/**
    + * Distributed query queue which uses a Zookeeper distributed semaphore to
    + * control queuing across the cluster. The distributed queue is actually two
    + * queues: one for "small" queries, another for "large" queries. Query size is
    + * determined by the Planner's estimate of query cost.
    + * <p>
    + * This queue is configured using system options:
    + * <dl>
    + * <dt><tt>exec.queue.enable</tt>
    + * <dt>
    + * <dd>Set to true to enable the distributed queue.</dd>
    + * <dt><tt>exec.queue.large</tt>
    + * <dt>
    + * <dd>The maximum number of large queries to admit. Additional
    + * queries wait in the queue.</dd>
    + * <dt><tt>exec.queue.small</tt>
    + * <dt>
    + * <dd>The maximum number of small queries to admit. Additional
    + * queries wait in the queue.</dd>
    + * <dt><tt>exec.queue.threshold</tt>
    + * <dt>
    + * <dd>The cost threshold. Queries below this size are small, at
    + * or above this size are large..</dd>
    + * <dt><tt>exec.queue.timeout_millis</tt>
    + * <dt>
    + * <dd>The maximum time (in milliseconds) a query will wait in the
    + * queue before failing.</dd>
    + * </dl>
    + * <p>
    + * The above values are refreshed every five seconds. This aids performance
    + * a bit in systems with very high query arrival rates.
    + */
    +
    +public class DistributedQueryQueue implements QueryQueue {
    +  private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(DistributedQueryQueue.class);
    +
    +  private class DistributedQueueLease implements QueueLease {
    +    private final QueryId queryId;
    +    private DistributedLease lease;
    +    private final String queueName;
    +    private long queryMemory;
    +
    +    public DistributedQueueLease(QueryId queryId, String queueName, DistributedLease
lease, long queryMemory) {
    +      this.queryId = queryId;
    +      this.queueName = queueName;
    +      this.lease = lease;
    +      this.queryMemory = queryMemory;
    +    }
    +
    +    @Override
    +    public String toString() {
    +      return String.format("Lease for %s queue to query %s",
    +          queueName, QueryIdHelper.getQueryId(queryId));
    +    }
    +
    +    @Override
    +    public long queryMemoryPerNode() { return queryMemory; }
    +
    +    @Override
    +    public void release() {
    +      DistributedQueryQueue.this.release(this);
    +    }
    +
    +    @Override
    +    public String queueName() { return queueName; }
    +  }
    +
    +  /**
    +   * Exposes a snapshot of internal state information for use in status
    +   * reporting, such as in the UI.
    +   */
    +
    +  @XmlRootElement
    +  public static class ZKQueueInfo {
    +    public final int smallQueueSize;
    +    public final int largeQueueSize;
    +    public final double queueThreshold;
    +    public final long memoryPerNode;
    +    public final long memoryPerSmallQuery;
    +    public final long memoryPerLargeQuery;
    +
    +    public ZKQueueInfo(DistributedQueryQueue queue) {
    +      smallQueueSize = queue.smallQueueSize;
    +      largeQueueSize = queue.largeQueueSize;
    +      queueThreshold = queue.queueThreshold;
    +      memoryPerNode = queue.memoryPerNode;
    +      memoryPerSmallQuery = queue.memoryPerSmallQuery;
    +      memoryPerLargeQuery = queue.memoryPerLargeQuery;
    +    }
    +  }
    +
    +  private long memoryPerNode;
    +  private int largeQueueSize;
    +  private int smallQueueSize;
    +  private SystemOptionManager optionManager;
    +  private ClusterCoordinator clusterCoordinator;
    +  private long queueThreshold;
    +  private long queueTimeout;
    +  private long refreshTime;
    +  private long memoryPerSmallQuery;
    +  private long memoryPerLargeQuery;
    +  private double largeToSmallRatio;
    +
    +  public DistributedQueryQueue(DrillbitContext context) {
    +    optionManager = context.getOptionManager();
    +    clusterCoordinator = context.getClusterCoordinator();
    +  }
    +
    +  @Override
    +  public void setMemoryPerNode(long memoryPerNode) {
    +    this.memoryPerNode = memoryPerNode;
    +    refreshConfig();
    +  }
    +
    +  private void assignMemory() {
    +
    +    // Divide up memory between queues using admission rate
    +    // to give more memory to larger queries and less to
    +    // smaller queries. We assume that large queries are
    +    // larger than small queries by a factor of
    +    // largeToSmallRatio.
    +
    +    double totalUnits = largeToSmallRatio * largeQueueSize + smallQueueSize;
    +    double memoryUnit = memoryPerNode / totalUnits;
    +    memoryPerLargeQuery = Math.round(memoryUnit * largeToSmallRatio);
    +    memoryPerSmallQuery = Math.round(memoryUnit);
    +
    +    logger.debug("Distributed queue memory config: total memory = {}, large/small memory
ratio = {}",
    +                 memoryPerNode, largeToSmallRatio);
    +    logger.debug("Small queue: {} slots, {} bytes per slot", smallQueueSize, memoryPerSmallQuery);
    +    logger.debug("Large queue: {} slots, {} bytes per slot", largeQueueSize, memoryPerLargeQuery);
    +  }
    +
    +  @Override
    +  public long getDefaultMemoryPerNode(double cost) {
    --- End diff --
    
    Changed.


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