The supplementary product SESAM/SQL-DCN, the distribution component for SESAM/SQL makes it possible to process SESAM/SQL databases located on different BS2000 computers with a single application program. The application program does not distinguish whether the data is located on a local or remote computer when processing these remote databases.
The application program contains no information on the location of the data, i.e. distribution is transparent from the point of view of the application. All communication operations are invisible to the user. This means that application programs can be used with no modifications on any of the computers within a network.
In the case of update transactions involving databases on different computers, SESAM/SQL-DCN uses a two-phase commit protocol to ensure that data consistency is maintained across the network. SESAM/SQL thus guarantees a consistent data set in the network even in the event of data modifications on a number of computers. Deadlocks and longlocks are recognized and resolved by the system beyond the boundaries of a single computer.
Depending on the field of application, the use of SESAM/SQL-DCN has the following advantages:
Higher performance:
The processing of user requests on different computers results in an increase in throughput.Higher level of availability:
If a computer fails, it does not mean that the whole system fails.Flexible organization:
Work processes do not have to be oriented to a central computer center.
Refer to section “Distributed processing with SESAM/SQL DCN” for further details on using SESAM/SQL-DCN.