Github user xuchuanyin commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2374#discussion_r196625258
--- Diff:
hadoop/src/main/java/org/apache/carbondata/hadoop/CsvRecordReader.java ---
@@ -0,0 +1,510 @@
+/*
+ * 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.hadoop;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.io.UnsupportedEncodingException;
+import java.math.BigDecimal;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.carbondata.common.annotations.InterfaceAudience;
+import org.apache.carbondata.common.annotations.InterfaceStability;
+import org.apache.carbondata.common.logging.LogService;
+import org.apache.carbondata.common.logging.LogServiceFactory;
+import org.apache.carbondata.core.constants.CarbonCommonConstants;
+import org.apache.carbondata.core.constants.CarbonV3DataFormatConstants;
+import org.apache.carbondata.core.datastore.block.SegmentProperties;
+import org.apache.carbondata.core.metadata.schema.table.CarbonTable;
+import
org.apache.carbondata.core.metadata.schema.table.column.CarbonColumn;
+import
org.apache.carbondata.core.metadata.schema.table.column.CarbonDimension;
+import
org.apache.carbondata.core.metadata.schema.table.column.CarbonMeasure;
+import
org.apache.carbondata.core.metadata.schema.table.column.ColumnSchema;
+import
org.apache.carbondata.core.scan.expression.exception.FilterUnsupportedException;
+import org.apache.carbondata.core.scan.filter.FilterUtil;
+import org.apache.carbondata.core.scan.filter.GenericQueryType;
+import org.apache.carbondata.core.scan.filter.executer.FilterExecuter;
+import org.apache.carbondata.core.scan.filter.intf.RowImpl;
+import org.apache.carbondata.core.scan.filter.intf.RowIntf;
+import org.apache.carbondata.core.scan.filter.resolver.FilterResolverIntf;
+import org.apache.carbondata.core.scan.model.QueryModel;
+import org.apache.carbondata.core.statusmanager.FileFormatProperties;
+import org.apache.carbondata.core.util.CarbonUtil;
+import org.apache.carbondata.core.util.DataTypeUtil;
+import org.apache.carbondata.hadoop.api.CarbonTableInputFormat;
+import org.apache.carbondata.hadoop.readsupport.CarbonReadSupport;
+import org.apache.carbondata.processing.loading.csvinput.CSVInputFormat;
+
+import com.univocity.parsers.csv.CsvParser;
+import com.univocity.parsers.csv.CsvParserSettings;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapreduce.InputSplit;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+import org.apache.hadoop.mapreduce.lib.input.FileSplit;
+
+/**
+ * scan csv file and filter on it
+ */
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+public class CsvRecordReader<T> extends AbstractRecordReader<T> {
--- End diff --
The procedure is alike, but the implementation is quite different. The most
import parts are converting origin data to internal row and converting origin
data to output row. StreamRecordReader, its origin source is ROW_V1 format
while in CsvRecordReader, its origin source is CSV format.
Besides, in StreamRecordReader there are more details, such as 'syncMark',
'rawRow', we do not need it in CSV.
Maybe we can extract the common code in utils or create a new abstraction
for ReadSupport or RecordReader.
---