  We present a complex data handling system for the COMPASS tokamak, operated
by IPP ASCR Prague, Czech Republic [1]. The system, called CDB (Compass
DataBase), integrates different data sources as an assortment of data
acquisition hardware and software from different vendors is used. Based on
widely available open source technologies wherever possible, CDB is vendor and
platform independent and it can be easily scaled and distributed. The data is
directly stored and retrieved using a standard NAS (Network Attached Storage),
hence independent of the particular technology; the description of the data
(the metadata) is recorded in a relational database. Database structure is
general and enables the inclusion of multi-dimensional data signals in multiple
revisions (no data is overwritten). This design is inherently distributed as
the work is off-loaded to the clients. Both NAS and database can be implemented
and optimized for fast local access as well as secure remote access. CDB is
implemented in Python language; bindings for Java, C/C++, IDL and Matlab are
provided. Independent data acquisitions systems as well as nodes managed by
FireSignal [2] are all integrated using CDB. An automated data post-processing
server is a part of CDB. Based on dependency rules, the server executes, in
parallel if possible, prescribed post-processing tasks.
