ydb/contrib/libs/apache/orc-format/README.md

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 Format

This project includes ORC specifications and the protobuf definition. Apache ORC Format 1.0.0 is desinged to be used for Apache ORC 2.0+.

Releases:

• Maven Central:
• Downloads: Apache ORC downloads
• Release tags: Apache ORC Format releases
• Plan: Apache ORC Format future release plan

The current build status:

• Main branch

Bug tracking: Apache ORC Format Issues

Building

./mvnw install