Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/928#discussion_r136667375
--- 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;
--- End diff --
Subtle point here. The rules for computing the memory are based on the
queue, but they can change at any moment. The value here captures the value
calculated at the moment that the lease is granted and is used to plan memory
for the query.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
