Ballista 0.3.0-alpha-202 Aug 2020
This is the second 0.3.0 alpha release and improves overall stability and UX.
This release contains the following improvements to the Rust project:
- It is now possible to specify configuration options such as parquet and csv reader batch sizes when submitting queries.
- Executors now use a simpler and more efficient worker thread model.
- The scheduler is slightly more efficient and uses a stateful client when communicating with executors, reducing the overhead of creating new network connections.
- The TPC-H example now accepts command-line arguments.
- The HashAggregateExec operator is re-implemented using async/await, removing the overhead of a dedicated thread.
- Explicit projections are now supported.
- Improvements to Docker packaging.
- Fixed bug where client-supplied schema was ignored.
This release contains the following improvements to the JVM project:
- Serde code added for new protobuf messages involved in distributed query execution.
- The scheduler is still extremely simple and inefficient.
- Distributed query performance is not optimized yet.