VoltDB

VoltDB is an in-memory database designed by several well-known database system researchers, including A.M. Turing Award winner Michael Stonebraker (who was involved in Ingres and POSTGRES), Sam Madden, and Daniel Abadi. It is an ACID-compliant RDBMS which uses a shared nothing architecture. It includes both enterprise and community editions. The community edition is licensed under the GNU Affero General Public License. Additional features in the commercially licensed VoltDB Enterprise version include durability, high availability, and Export integrations. VoltDB implements the design of the academic H-Store project.^[1]

Architecture

VoltDB is a scale-out NewSQL relational database that supports SQL access from within pre-compiled Java stored procedures. The unit of transaction is the stored procedure, which is Java interspersed with SQL. VoltDB relies on horizontal partitioning down to the individual hardware thread to scale, k-safety (synchronous replication) to provide high availability, and a combination of continuous snapshots and command logging for durability (crash recovery).

VoltDB uses a shared-nothing architecture to achieve database parallelism. Data and the processing associated with it are distributed among all the CPU cores within the servers composing a single VoltDB cluster. By extending its shared-nothing foundation to the per-core level, VoltDB scales with the increasing core-per-CPU counts on modern commodity servers.

By making stored procedures the unit of transaction and executing them at the partition containing the necessary data, it is possible to eliminate round trip messaging between SQL statements. Stored procedures are executed serially and to completion in a single thread without any locking or latching, similar to the LMAX architecture.^[2] Because data is in memory and local to the partition, a stored procedure can execute in microseconds. VoltDB's stored procedure initiation scheme allows all nodes to initiate stored procedures while ensuring that there is a single serializable global order.^[3]

VoltDB is fully ACID compliant. Data is durable to disk. Durability is ensured by continuous snapshots; asynchronous command logging, which creates both snapshots and a log of all transactions between snapshots; and synchronous command logging, which writes transactions to the log after the transaction completes and before it is committed to the database. This ensures no transactions are committed that are not logged and no transactions are lost.

VoltDB version 5.1, released in March 2015, introduces new Database Replication functionality, removing any single point of failure. DR now provides simultaneous, parallel replication of multiple partitions and use of binary logs of transaction results, saving the replica from having to replay the transaction. VoltDB v5.0 introduced a new database monitoring and management tool, the VoltDB Management Center (VMC for short). VMC provides browser-based one-stop monitoring and configuration management of the VoltDB database, including graphs for cluster throughput and latency as well as CPU and memory usage for the current server.

Versions history

• VoltDB Community Edition 1.0 - first general availability in May 2010, as an open source product distributed under the GPLv3.
• VoltDB 1.2 was released in October 2010, under both open source (VoltDB Community Edition) and proprietary (VoltDB Enterprise Edition) licenses.
• VoltDB 2.0 was released in September 2011, and included a high performance durability feature called command logging (VoltDB Enterprise Edition only).
• VoltOne was released in October 2011. It is a brand name for a single-server version of VoltDB Enterprise Edition.
• VoltDB 2.5 was released in April 2012. It included database replication, providing cluster-wide replication and fail-over within/across data centers (VoltDB Enterprise Edition only).
• VoltDB 3.0 was released in January 2013. It lowered operational latency, offered live schema changes, added more SQL and offered high-performance export (VoltDB Enterprise Edition only).^[4]
• VoltDB 4.0 was released in January 2014. It enhanced In-memory analytics capabilities with a host of new SQL support, greatly improved analytic read throughput performance, enabled running clusters grow elastically without blocking and added support for Groovy stored procedures, MySQL migration utility and Online training along with Volt Vanguard Certification.^[5]
• VoltDB 5.0 was released in January 2015. The release included integrations into the Hadoop/Big Data ecosystem, including export integrations (Kafka; HDFS Export; HTTP Export; and RabbitMQ Export) as well as import integrations (Kafka Loader; the JDBC Loader; the VoltDB Hadoop OutputFormat implementation; a Vertica UDx; and support for Apache Hive and Apache Pig.) VoltDB 5.0 also includes additional SQL support and availability of the VoltDB Management Center, a browser-based monitoring and configuration management dashboard.

See also

• Comparison of database tools
• Comparison of relational database management systems

References

1. ↑ http://hstore.cs.brown.edu/
2. ↑ http://martinfowler.com/articles/lmax.html
3. ↑ http://community.voltdb.com/node/118#comment-271
4. ↑ "Introducing VoltDB 3.0". Retrieved 5 February 2013. 
5. ↑ https://voltdb.com/announcing-voltdb-4-0-enhanced-in-memory-analytics-and-online-elasticity/

External links

• Official website
• VoltDB at Open Hub
• Curt Monash (25 May 2010). "VoltDB finally launches". DBMS 2. Retrieved 2011-07-09. 
• "VoltDB Announces Version 5.0". VoltDB, Inc. 28 January 2015. Retrieved 2015-03-29. 
• "Michael Stonebraker, VoltDB Co-Founder and Real-time Data Pioneer, Wins ACM 2014 A.M. Turing Award". VoltDB, Inc. 26 March 2015. Retrieved 2015-03-29. 
• "VoltDB Aims for Fast Big Data Development". ADTmag. 29 January 2015. Retrieved 2015-03-29.