Github user sohami commented on a diff in the pull request:
https://github.com/apache/drill/pull/1223#discussion_r182628559
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/unnest/UnnestImpl.java
---
@@ -0,0 +1,137 @@
+/*
+ * 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.physical.impl.unnest;
+
+import com.google.common.collect.ImmutableList;
+import org.apache.drill.exec.exception.SchemaChangeException;
+import org.apache.drill.exec.ops.FragmentContext;
+import org.apache.drill.exec.physical.base.LateralContract;
+import org.apache.drill.exec.record.BatchSchema.SelectionVectorMode;
+import org.apache.drill.exec.record.RecordBatch;
+import org.apache.drill.exec.record.TransferPair;
+import org.apache.drill.exec.vector.ValueVector;
+import org.apache.drill.exec.vector.complex.RepeatedValueVector;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+
+/**
+ * Contains the actual unnest operation. Unnest is a simple transfer
operation in this impelementation.
+ * For use as a table function, we will need to change the logic of the
unnest method to operate on
+ * more than one row at a time and remove any dependence on Lateral
+ * {@link org.apache.drill.exec.physical.impl.flatten.FlattenTemplate}.
--- End diff --
Little confused why `FlattenTemplate` is referenced here.
---
