Apache ORC
ORC is a self-describing type-aware columnar file format designed for Hadoop workloads. It is optimized for large streaming reads, but with integrated support for finding required rows quickly. Storing data in a columnar format lets the reader read, decompress, and process only the values that are required for the current query. Because ORC files are type-aware, the writer chooses the most appropriate encoding for the type and builds an internal index as the file is written. Predicate pushdown uses those indexes to determine which stripes in a file need to be read for a particular query and the row indexes can narrow the search to a particular set of 10,000 rows. ORC supports the complete set of types in Hive, including the complex types: structs, lists, maps, and unions.
ORC File Library
This project includes both a Java library and a C++ library for reading and writing the Optimized Row Columnar (ORC) file format. The C++ and Java libraries are completely independent of each other and will each read all versions of ORC files.
Releases:
- Latest: Apache ORC releases
- Maven Central:
- Downloads: Apache ORC downloads
- Release tags: Apache ORC release tags
- Plan: Apache ORC future release plan
The current build status:
- Main branch
Bug tracking: Apache Jira
The subdirectories are:
- c++ - the c++ reader and writer
- cmake_modules - the cmake modules
- docker - docker scripts to build and test on various linuxes
- examples - various ORC example files that are used to test compatibility
- java - the java reader and writer
- proto - the protocol buffer definition for the ORC metadata
- site - the website and documentation
- tools - the c++ tools for reading and inspecting ORC files
Building
- Install java 1.8 or higher
- Install maven 3.8.4 or higher
- Install cmake
To build a release version with debug information:
% mkdir build
% cd build
% cmake ..
% make package
% make test-out
To build a debug version:
% mkdir build
% cd build
% cmake .. -DCMAKE_BUILD_TYPE=DEBUG
% make package
% make test-out
To build a release version without debug information:
% mkdir build
% cd build
% cmake .. -DCMAKE_BUILD_TYPE=RELEASE
% make package
% make test-out
To build only the Java library:
% cd java
% ./mvnw package
To build only the C++ library:
% mkdir build
% cd build
% cmake .. -DBUILD_JAVA=OFF
% make package
% make test-out