Github user jackylk commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2823#discussion_r227620816
--- Diff:
core/src/main/java/org/apache/carbondata/core/scan/scanner/LazyBlockletLoad.java
---
@@ -0,0 +1,158 @@
+/*
+ * 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.scan.scanner;
+
+import java.io.IOException;
+
+import org.apache.carbondata.core.datastore.FileReader;
+import org.apache.carbondata.core.datastore.chunk.AbstractRawColumnChunk;
+import
org.apache.carbondata.core.datastore.chunk.impl.DimensionRawColumnChunk;
+import
org.apache.carbondata.core.datastore.chunk.impl.MeasureRawColumnChunk;
+import org.apache.carbondata.core.scan.executor.infos.BlockExecutionInfo;
+import org.apache.carbondata.core.scan.processor.RawBlockletColumnChunks;
+import org.apache.carbondata.core.stats.QueryStatistic;
+import org.apache.carbondata.core.stats.QueryStatisticsConstants;
+import org.apache.carbondata.core.stats.QueryStatisticsModel;
+
+/**
+ * Reads the blocklet column chunks lazily, it means it reads the column
chunks from disk when
+ * execution engine wants to access it.
+ * It is useful in case of filter queries with high cardinality columns.
+ */
+public class LazyBlockletLoad {
+
+ private RawBlockletColumnChunks rawBlockletColumnChunks;
+
+ private BlockExecutionInfo blockExecutionInfo;
+
+ private LazyChunkWrapper[] dimLazyWrapperChunks;
+
+ private LazyChunkWrapper[] msrLazyWrapperChunks;
--- End diff --
can we unify the processing of `dimLazyWrapperChunks` and
`msrLazyWrapperChunks` so that we can use one flow for them?
---
