History[03]

Kx Systems originaly released kdb in 1998. It was a database built on the K programming language developed by Arthur Whitney. In 2003, Kx Systems released kdb+ as a 64-bit version of kdb.

Compression[04]

Kdb+ supports compression in following ways:

• A built-in WebSocket server which supports WebSocket compression standard.

• In-flight compression between hosts.

• On-disk compression, which supports 4 algorithms:

• kdb+ algorithm

• gzip

• Google Snappy

• lzh4c

Concurrency Control[05]

Kdb+ supports for concurrent manipulation of data.

Data Model[05]

Kdb+ uses relational model.

Foreign Keys[05]

Kdb+ supports referential integrity.

Hardware Acceleration[04]

Kdb+ doesn't rely on any hardware acceleration.

Indexes[05]

Kdb+ supports secondary indexes.

Isolation Levels[06]

Kdb+ only supports SERIALIZABLE isolation level.

Joins[04]

Kdb+ supports sql standard joins.

Logging[04]

Kdb+ uses physical logging. When new data comes from sources, in-memory event-engine will log to on-disk log file to ensure durability.

Query Compilation[04]

q is interpreted language.

Query Execution[04][07]

q is vector processing languages.

Query Interface[05]

Kdb+ supports following interfaces:

• ODBC/JDBC

• C/C++

• Java

• C#

• Python

• R

Storage Architecture[04]

Kdb+ has both in-memory and on-disk storage. New data is held in memory and is flushed to disk at daily basis under control of the event-engine.

Storage Model[03]

Kdb+ uses DSM both for in-memory and on-disk storage.

Stored Procedures[03]

Kdb+ supports UDF.

System Architecture[04]

Kdb+ uses Lambda architecture has the following properties:

• Data currently using stores in memory, while historical data is stored on disk.

• New data come in from streaming sources.

• Event-engine distribute data to downstream subscribers, including real-time database engine and streaming query engine.

• Real-time database projects its content down to on-disk historical database for analytic use at daily basis, controlled by event-engine.

Views[04]