1 files changed, 63 insertions, 0 deletions
diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/planner/fragment/QueryParallelizer.java b/exec/java-exec/src/main/java/org/apache/drill/exec/planner/fragment/QueryParallelizer.java
new file mode 100644
index 000000000..097f4b249
--- /dev/null
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/planner/fragment/QueryParallelizer.java
@@ -0,0 +1,63 @@
+/*
+ * 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.planner.fragment;
+
+import org.apache.drill.common.exceptions.ExecutionSetupException;
+import org.apache.drill.exec.proto.BitControl.QueryContextInformation;
+import org.apache.drill.exec.proto.CoordinationProtos.DrillbitEndpoint;
+import org.apache.drill.exec.proto.UserBitShared.QueryId;
+import org.apache.drill.exec.rpc.user.UserSession;
+import org.apache.drill.exec.server.options.OptionList;
+import org.apache.drill.exec.work.QueryWorkUnit;
+
+import java.util.Collection;
+
+/**
+ * This class parallelizes the query plan. Once the optimizer finishes its job by producing a
+ * optimized plan, it is the job of this parallelizer to generate a parallel plan out of the
+ * optimized physical plan. It does so by using the optimizers estimates for row count etc.
+ * There are two kinds of parallelizers as explained below. Currently the difference in
+ * both of these parallelizers is only in the memory assignment for the physical operators.
+ *
+ * a) Default Parallelizer: It optimistically assumes that the whole cluster is running only the
+ *    current query and based on heuristics assigns the optimal memory to the buffered operators.
+ *
+ * b) Queue Parallelizer: This parallelizer computes the memory that can be allocated at best based
+ *    on the current cluster state(as to how much memory is available) and also the configuration
+ *    of the queue that it can run on.
+ */
+public interface QueryParallelizer extends ParallelizationParameters {
+
+  /**
+   * This is the only function exposed to the consumer of this parallelizer (currently Foreman) to parallelize
+   * the plan. The caller transforms the plan to a fragment tree and supplies the required information for
+   * the parallelizer to do its job.
+   * @param options List of all options that are set for the current session.
+   * @param foremanNode Endpoint information of the foreman node.
+   * @param queryId Unique ID of the query.
+   * @param activeEndpoints Currently active endpoints on which the plan can run.
+   * @param rootFragment root of the fragment tree of the transformed physical plan
+   * @param session user session object.
+   * @param queryContextInfo query context.
+   * @return Executable query plan which contains all the information like minor frags and major frags.
+   * @throws ExecutionSetupException
+   */
+  QueryWorkUnit generateWorkUnit(OptionList options, DrillbitEndpoint foremanNode, QueryId queryId,
+                                 Collection<DrillbitEndpoint> activeEndpoints, Fragment rootFragment,
+                                 UserSession session, QueryContextInformation queryContextInfo) throws ExecutionSetupException;
+}