wangfei created SPARK-3720:
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Summary: support ORC in spark sql
Key: SPARK-3720
URL: https://issues.apache.org/jira/browse/SPARK-3720
Project: Spark
Issue Type: New Feature
Components: SQL
Affects Versions: 1.1.0
Reporter: wangfei
The Optimized Row Columnar (ORC) file format provides a highly efficient way to
store data on hdfs.ORC file format has many advantages such as:
1 a single file as the output of each task, which reduces the NameNode's load
2 Hive type support including datetime, decimal, and the complex types (struct,
list, map, and union)
3 light-weight indexes stored within the file
skip row groups that don't pass predicate filtering
seek to a given row
4 block-mode compression based on data type
run-length encoding for integer columns
dictionary encoding for string columns
5 concurrent reads of the same file using separate RecordReaders
6 ability to split files without scanning for markers
7 bound the amount of memory needed for reading or writing
8 metadata stored using Protocol Buffers, which allows addition and removal of
fields
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