Comdb2

{{short description|Database management system, relational, open source, developed by Bloomberg LP}}

{{Infobox software

| title = Comdb2

| name = Comdb2

| logo =

| screenshot =

| caption =

| collapsible =

| author = Comdb2 Team

| developer = Comdb2 team, and other open source component developers

| released = {{Start date and age|2016|01|01|df=yes}}{{Cite web |url=https://bloomberg.github.io/comdb2/ |title=Comdb2 |website=Comdb2 Website |access-date=2020-11-18}}

| discontinued =

| latest release version = 7.0

| latest release date =

| programming language = C

| operating system = Linux, Solaris, AIX

| platform =

| size =

| language = English

| genre = RDBMS

| license = Apache v2, BSD License, MIT License, Sleepycat License{{Cite web|url=https://github.com/bloomberg/comdb2/blob/86424e3b28ea7a522c33b2c22d8c27112d1d25a3/LICENSE|title=Comdb2 Licenses|website=Comdb2 Licenses}}

| website = {{URL|https://bloomberg.github.io/comdb2/}}

}}

Comdb2 is an open source, highly available clustered RDBMS developed by Bloomberg LP, built on optimistic concurrency control techniques. It provides multiple isolation levels, including Snapshot and Serializable Isolation. Read/Write transactions run on any node, with the client library transparently negotiating connections to lowest cost (latency) node which is available. Comdb2 implements queues for publisher-to-subscriber message delivery. Queues can be combined with table triggers for time-consistent log distribution.

Comdb2 supports the SQLite dialect of SQL with some modifications,{{Cite web|title=SQL language {{!}} Comdb2 Documentation|url=https://bloomberg.github.io/comdb2/sql.html|access-date=2020-11-18|website=bloomberg.github.io}} and embeds the Lua scripting language. Comdb2 maintains a fork of Berkeley DB to provide the key–value database backend to SQLite.

Comdb2 architecture was described in detail in this 2016 technical paper.http://www.vldb.org/pvldb/vol9/p1377-scotti.pdf {{Bare URL PDF|date=March 2022}}