DBMS Extensions – Real-Time Data Replication

The tcVISION DBMS Extensions for IMS/DB, DL/I, VSAM, DB2, ADABAS, CA-Datacom and CA-IDMS allow the capturing of changed data in real-time or near real-time directly at the database level. 

The implementation of the DBMS-Extensions also provides a secure data storage, even across restart of the DBMS.

Processing steps of a tcVISION 'DBMS Extension':

• Capturing of changed data directly at the database level
• Transfer of changed data to a "Pool storage"
• Parallel processing of changed data from the pool
• Propagation of data to the target system
• Implementation into the target database

Example:

DL/I Real-Time Capture and propagation into DB2 under zVM

• Import of Metadata
• Creation of Collector Pool
• Definition of the Processing scripts
• Defining the data mapping
• Test and Implementation (Control Board)

(1) Metadata import

Via a graphical Windows interface it is easy to setup the metadata import, which uses the data definition details of the different data stores being replicated. For the current example tcVISION uses the PSB and DBD information within DL/I.

The following is a customer implementation that is in production use.

(2) Creation of a collector/pool combination

The collector acts as DBMS Extension and collects the changed data. The changed data that qualifies for further processing is transferred to a pool.

(3) Definition of the processing scripts

The changed data in the pool is propagated into the target system by a processing script.

The definition of the script is an easy wizard based step and part of the project wizard shown below.

(4) Assignment of target tables

Target tables can be automatically created. Alternatively tables that already exist in the target system can be assigned.

(5) Test and implementation

The activation of the new project is performed using the tcVISION Control Board.

Technical background:

Why does the customer use the tcVISION DBMS-Extension in production?

Based upon 40 DLI segments and approx. 200,000,000 data records, between 180,000 and 200,000 data changes are performed by the applications daily. A traditional data transfer implementation for the synchronization is not possible due to the large amount of changed data.

The tcVISION DBMS-Extension captures the changes performed by the Online- and Batch DL/I-programs and performs a real-time propagation of the changed data to the DB2 system. If the DB2 system is not available as the target system, the tcVISION processing automatically switches to a VSAM KSDS file. This guarantees a high degree of reliability.