Near Real-Time data capture is accomplished on most platforms using the transaction log, maintained by the database manager for the purpose of database recovery. Historically, these logs have also been the source of data for other purposes including audit or replication. Generally it is necessary and possible to configure the database manager to include additional information in the log for use by these non-recovery related activities.
All changes (Inserts, Updates, and Deletes) to a UDB (Db2/LUW) Database are logged by the native Recovery Log facility. The Connect CDC (SQData) UDB Log Reader Capture agent extracts changed data from the recovery log (active and/or archive) using the Instrumentation Facility Interface (IFI). There is generally one Data Capture component per UDB Instance. Refer to the IBM's UDB (Db2/LUW) Server documentation for further information on the Recovery Log facility.