Parquet

• File format
• Thrift definition

ORC

• ORC Specification v1
  • v2 specification exists, but it seems there is no progress since 2018.
• protobuf definition

Links

• An Empirical Evaluation of Columnar Storage Formats
• Exploiting Cloud Object Storage for High-Performance Analytics
• Amazon’s Exabyte-Scale Migration from Apache Spark to Ray on Amazon EC2