Github user gparai commented on a diff in the pull request:
https://github.com/apache/drill/pull/729#discussion_r102291099
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/unpivot/UnpivotMapsRecordBatch.java
---
@@ -0,0 +1,276 @@
+/**
+ * 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
+ * <p/>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p/>
+ * 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.unpivot;
+
+import java.util.List;
+import java.util.Map;
+
+import org.apache.drill.common.types.TypeProtos.MajorType;
+import org.apache.drill.common.types.TypeProtos.MinorType;
+import org.apache.drill.exec.exception.OutOfMemoryException;
+import org.apache.drill.exec.exception.SchemaChangeException;
+import org.apache.drill.exec.expr.TypeHelper;
+import org.apache.drill.exec.ops.FragmentContext;
+import org.apache.drill.exec.physical.config.UnpivotMaps;
+import org.apache.drill.exec.record.AbstractSingleRecordBatch;
+import org.apache.drill.exec.record.MaterializedField;
+import org.apache.drill.exec.record.RecordBatch;
+import org.apache.drill.exec.record.TransferPair;
+import org.apache.drill.exec.record.VectorContainer;
+import org.apache.drill.exec.record.VectorWrapper;
+import org.apache.drill.exec.vector.ValueVector;
+import org.apache.drill.exec.vector.complex.MapVector;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+
+/**
+ * Unpivot maps. Assumptions are:
+ * 1) all child vectors in a map are of same type.
+ * 2) Each map contains the same number of fields and field names are
also same (types could be different).
+ *
+ * Example input and output:
+ * Schema of input:
+ * "schema" : BIGINT - Schema number. For each schema change
this number is incremented.
+ * "computed" : BIGINT - What time is it computed?
+ * "columns" : MAP - Column names
+ * "region_id" : VARCHAR
+ * "sales_city" : VARCHAR
+ * "cnt" : VARCHAR
+ * "statscount" : MAP
+ * "region_id" : BIGINT - statscount(region_id) - aggregation over
all values of region_id
+ * in incoming batch
+ * "sales_city" : BIGINT - statscount(sales_city)
+ * "cnt" : BIGINT - statscount(cnt)
+ * "nonnullstatcount" : MAP
+ * "region_id" : BIGINT - nonnullstatcount(region_id)
+ * "sales_city" : BIGINT - nonnullstatcount(sales_city)
+ * "cnt" : BIGINT - nonnullstatcount(cnt)
+ * .... another map for next stats function ....
+ *
+ * Schema of output:
--- End diff --
For now, we stick to the original reviewed design. We can revisit the
design later, if required.
---
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.
---
