The H-Store project is proud to announce the release of the latest version of its research OLTP database management system. This version has many new features and improvements developed by students in Brown University’s seminar course on NewSQL systems, as well as four new benchmarks (voter, wikipedia, ycsb, and tpce), faster client connection processing, and improved regression testing.

Major highlights of this release:

1. New Feature: Added new command logger that can write out successfully executed transactions to a log file at each node. The logger uses a separate thread and group commits transactions with minimum overhead to throughput. This log can then be replayed for recovery (work in progress). [ceb6a49] [ae4c82b] [abdc371] [99ffc9f] [d53afcc]
2. New Feature: Defer the execution of queries in single-partition transactions until a later point in time when the partition’s execution thread is idle. [8037dfe]
3. New Feature: Added support for ad-hoc queries. This allows you to execute single queries that are not part of a stored procedure. The H-Store distribution also provides a command-line terminal to connect to an H-Store cluster. [faf297c] [fda4c41]
4. New Benchmarks: VoltDB’s voter benchmark, Wikipedia, Yahoo!’s ycsb benchmark, and TPC-E (per David DeWitt’s persistent request). [5992d22] [0caa40c] [9cc5895] [#68]
5. Complete overhaul of the server-side infrastructure from processing incoming transaction requests from clients. This great improves scalability for workloads with very short single-partition transactions on machines with many cores (>10). [d03ba80]
6. Optimized and improve client side execution in benchmark framework. Reduced CPU overhead of each client thread. Added support for multiple JVM instances per client host. Added ability to specify whether client threads share a connection to the database cluster. [9f3c2d62] [df150881] [e44b3314]
7. Improve query plan optimization for distributed OLAP-style queries [e889abb] [89d06c8]
8. Major refactoring of the source code repository: all of the benchmark code has been moved in src/benchmarks. [a321847]

The source code for this release can be downloaded via Github:

https://github.com/apavlo/h-store/tarball/release-2012-06