Github user xuchuanyin commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2411#discussion_r200018301
--- Diff:
core/src/main/java/org/apache/carbondata/core/datamap/dev/expr/DataMapWrapperSchema.java
---
@@ -0,0 +1,87 @@
+/*
+ * 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.carbondata.core.datamap.dev.expr;
+
+import org.apache.carbondata.core.metadata.schema.table.DataMapSchema;
+
+/**
+ * schema for datamap wrapper
--- End diff --
Because currently a DatamapWrapper contains more than one datamap, this
class is to describle its schema.
For example a AndDatamapWrapper contains BloomFilterin its left and Lucene
in its right, then its schema would be AND(BloomFilter, Lucene).
This DataMapWrapperSchema is used for explain output
---
