Major highlights of this release:
- Significant optimizations of single-partition transactions. Added heavy use of object pooling and cached query batch planning.
- Added support for general transactions that touch an arbitrary number of partitions.
- Improved distributed query planner. Unlike VoltDB’s query planner, we can now push down projection operators and parallelize all aggregates supported by H-Store (except for COUNT(DISTINCT)). This greatly reduces the amount of data that needs to be sent from all of the partitions to the initiating partition.
Update: VoltDB’s query planner now does predicate push-down as of May 2011.
- The system can predict the execution path of arbitrary transactions. The developer no longer needs to annotate stored procedures with the @ProcInfo that VoltDB requires (more details coming soon).
- Many bug fixes for interacting with the transaction coordinator (support for larger batch sizes).
- New tuning parameters.
- Improved the H-Store Catalog Viewer Tool
The source code for this release can be download via anonymous SVN:
Or from a pre-packaged source code tarball.