Github user arina-ielchiieva commented on a diff in the pull request:
https://github.com/apache/drill/pull/928#discussion_r142944163
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/work/foreman/rm/EmbeddedQueryQueue.java
---
@@ -0,0 +1,147 @@
+/*
+ * 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.Semaphore;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.drill.common.config.DrillConfig;
+import org.apache.drill.exec.ExecConstants;
+import org.apache.drill.exec.proto.UserBitShared.QueryId;
+import org.apache.drill.exec.proto.helper.QueryIdHelper;
+import org.apache.drill.exec.server.DrillbitContext;
+
+/**
+ * Query queue to be used in an embedded Drillbit. This queue has scope of
only
+ * the one Drillbit (not even multiple Drillbits in the same process.)
Primarily
+ * intended for testing, but may possibly be useful for other embedded
+ * applications.
+ * <p>
+ * Configuration is via config parameters (not via system options as for
the
+ * distributed queue.)
+ * <dl>
+ * <dt><tt>drill.queue.embedded.enabled</tt></dt>
+ * <dd>Set to true to enable the embedded queue. But, this setting has
effect
+ * only if the Drillbit is, in fact, embedded.</dd>
+ * <dt><tt>drill.queue.embedded.size</tt></dt>
+ * <dd>The number of active queries, all others queue. There is no upper
limit
+ * on the number of queued entries.</dt>
+ * <dt><tt>drill.queue.embedded.timeout_ms</tt></dt>
+ * <dd>The maximum time a query will wait in the queue before failing.</dd>
+ * </dl>
+ */
+
+public class EmbeddedQueryQueue implements QueryQueue {
+
+ public static String EMBEDDED_QUEUE = "drill.exec.queue.embedded";
+ public static String ENABLED = EMBEDDED_QUEUE + ".enable";
+ public static String QUEUE_SIZE = EMBEDDED_QUEUE + ".size";
+ public static String TIMEOUT_MS = EMBEDDED_QUEUE + ".timeout_ms";
+
+ public class EmbeddedQueueLease implements QueueLease {
+
+ private final QueryId queryId;
+ private boolean released;
--- End diff --
Is never assigned...
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