commit | c210565e9e559feb9ec64ffea967a9a36e9d06dc | [log] [tgz] |
---|---|---|
author | david.zanter <David.Zanter@sas.com> | Wed Dec 04 15:16:22 2019 -0500 |
committer | Owen O'Malley <omalley@apache.org> | Fri Dec 06 08:38:41 2019 -0800 |
tree | 692821e084aa71619b0f8bfffed8cea1e99fc1e9 | |
parent | 949c7444ef98680026d9f2b93d7299b76cdfb030 [diff] |
ORC-574: Use const references for string statistics. A large portion of cpu in write scenarios is being used in std::string alloc/delete due to the getMaximum/Minimum returning std:string copies. Changing the getMaximum/getMinimum methods to return const vals will prevent these alloc/copy/deletes from occurring. This results in about a 30% cpu boost to write. Fixes #574 Signed-off-by: Owen O'Malley <omalley@apache.org>
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.
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. But the C++ library only writes the original (Hive 0.11) version of ORC files, and will be extended in the future.
Releases:
The current build status:
Bug tracking: Apache Jira
The subdirectories are:
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 % mvn package
To build only the C++ library:
% mkdir build % cd build % cmake .. -DBUILD_JAVA=OFF % make package % make test-out