The H-Store project is releasing the latest version of its experimental OLTP DBMS. This latest release includes several performance optimizations for single-partition transactions, as well as new support for internal profiling of various performance metrics.

Major highlights of this release:

1. The BatchPlanner can now quickly determine whether a query batch will execute entirely on the local partition and will use a cached batch plan if it is. This provides a significant speed improvement for single-partition transactions. (r2343, r2344)
2. Added the ability to pin the ExecutionSite’s Java thread to a fixed number of cores (using taskset). All other HStoreSite threads are only allowed to execute on the remaining CPU cores. See the ${site.cpu_affinity} parameter documentation for more information. (r2339)
3. New parameter ${client.txn_hints} that allows clients to route transaction requests to the proper node in the cluster, thereby reducing two extra network hops. (r2312, r2313)
4. Fixed automatic distribution of vertically partitioned tables when using the @LoadMultipartitionTable sysproc. (r2317)
5. Fixed hstore-benchmark so that it exits with a non-zero status code when the benchmark fails to execute to completion. (r2266)
6. H-Store now includes an automatic deployment script for Amazon EC2 based on Fabric and Boto. More information can be found here.

The source code for this release can be downloaded via anonymous SVN:

https://database.cs.brown.edu/svn/hstore/tags/release-2011-09