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MemSQL logo.
Developer(s) MemSQL Inc.
Stable release 3.1 / August 11, 2014; 3 months ago (2014-08-11)[1]
Written in C++
Operating system Linux
License Proprietary License

MemSQL is a distributed, in-memory database that is part of the NewSQL movement.[2] It is an ACID-compliant RDBMS that most notably converts SQL into C++ through code generation.[3] It is being developed by MemSQL Inc., that was founded in 2011 and is a graduate of the Y Combinator startup program. MemSQL Inc. has raised more than $5 million to date from a variety of investors including First Round Capital, IA Ventures, NEA, and several prominent angels including Paul Buchheit, Max Levchin, Aaron Levie, and Ashton Kutcher.[4] MemSQL Inc. launched its database to the public on June 18, 2012.[5]

Core Technology[edit]

MemSQL combines lock-free data structures and a just-in-time (JIT) compiler for processing highly volatile workloads.[6] More specifically, MemSQL implements lock-free hash tables and lock-free skiplists in memory for fast random access to data. Queries sent to the MemSQL server are converted into C++ and compiled through GCC.[7] Queries are stripped of their parameters and the query template is stored as a shared object which is subsequently matched against incoming queries to the system. Code generation and the execution of pre-compiled query plans removes interpretation along hot code paths, providing highly efficient code paths that minimize the number of CPU instructions required.

MemSQL is wire-compatible with MySQL.[8] Applications can connect to MemSQL through standard ODBC/JDBC connectors as well as MySQL clients and drivers.[9]


Even though MemSQL stores data in memory, MemSQL is durable by implementing a write-ahead log and snapshots (similar to checkpoints). On default settings, as soon as a transaction is acknowledged in memory, the database will write the transaction to disk as fast as the disk will allow.[10]


MemSQL supports a native replication protocol that ships its transactional log to slaves. MemSQL currently supports master-slave replication.

Distributed Architecture[edit]

MemSQL is a distributed database that works by the concept of aggegators and leaf nodes.[11] An aggregator is responsible for breaking up the query across the relevant leaf nodes and aggregating results back to the client. A leaf node is a MemSQL database. MemSQL uses hash partitioning to distribute data uniformly across the number of leaf nodes.[12] MemSQL made the distributed version of its system generally available on April 23, 2013[13] with a trial edition available for download on their website.[14]

Version History[edit]

MemSQL 1b - first general availability in June, 2012.[15]
MemSQL 1c - minor feature update, released July 2012.
MemSQL 1.8 - replication and expanded SQL surface area, released December 2012
MemSQL 2.0 - general availability of distributed system.[16] First release of MemSQL Watch operational dashboard.[17]
MemSQL 2.5 - JSON Data type[18]
MemSQL 3.0 - Columnar data store [19]
MemSQL 3.1 - Views, Cross-Datacenter replication [20]


External links[edit]