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Akonadi Server Database Internals

This page contains information about how the Akonadi server uses its internal SQL database. This is purely for Akonadi server developers, you are NOT supposed to use the database yourself, by-passing Akonadi!

Database Schema

  • Visualization
  • Code is in server/src/storage
    • akonadidb.xml contains the schema in an XML format
    • dbinitializer* contains the code to create tables out of that
    • updatedb.xml contains schema update instructions
    • dbupdater.* executes those


Akonadi can use different SQL backends. The following documents backend-specific details.

In general, backend specific configuration and setup code can be found in server/src/storage/dbconfig*.

There are three possible operation modes for backends, most only support a subset:

  • Embedded: No server process, database is completely integrated into the Akonadi process
  • Internal server: Akonadi manages the database server process itself, taking care of starting/stopping and configuring it.
  • External server: Akonadi connects to an already running database server.

Selecting and configuring the different backends can be done in ~/.config/akonadi/akonadiserverrc, details on the available options can be found here: akonadiserverrc options


Status: working, default backend for desktop systems

Supported modes: Internal, External

MySQL server configuration files for the internal mode can be found here: server/src/storage/mysql-global*.conf.


Status: working with limitations, default backend for mobile systems

Supported modes: Embedded

Known issues:


Status: Working

Supported modes: Internal, External

Known issues:

  • Manual dump and import are required after upgrading the Postgres server installation if the database scheme changes.


Status: not working

Supported modes: External

Proof-of-concept work was done during Akademy 2010, up to the point where the database could be created successfully. Known issues:

  • Some column names used by Akonadi are Virtuoso keywords
  • Some of the first INSERT query fails with a signed vs. unsigned int mismatch/overflow.

Completion of Virtuoso support is considered non-trivial and probably requires a lot of work on the Akonadi side, the SQL dialect is too different from what we support so far.


Status: not working

Supported modes: Embedded

Development stopped, MySQL/Embedded does not support transactions.



akonadiconsole has support for browsing the database and running arbitrary SQL queries. See Development/Tutorials/Akonadi/Application.


There are convenience scripts for running mysqld in the configuration used by Akonadi as well as (and probably more useful) running the MySQL command line client connected to the Akonadi database. See server/src/storage/akonadi-mysql-[client|server].sh.

This page was last modified on 3 December 2012, at 02:15. This page has been accessed 13,506 times. Content is available under Creative Commons License SA 3.0 as well as the GNU Free Documentation License 1.2.
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