IBM InfoSphere CDC Vs Long Running Transactions
InfoSphere Change Data Capture (ISCDC) which is part of IBM InfoSphere Data Replication has the concept of Restart Position via bookmark which keeps advancing as the records are replicated and applied at the target that helps tracking CDC to keep the record of how much data have already been replicated so that CDC when restarted can start from this position. There was a customer using Oracle as a source from which the data was replicated, and it was observed that InfoSphere CDC was holding up transaction inspite of not having any open transactions in the V$TRANSACTION. Later it turned out to be that the open transaction was identified from the GV$TRANSACTION table. These are global transactions that can occur in the Oracle RAC environment. So, InfoSphere CDC holding up the transactions were found to be very much legitimate. Long transactions in the database (and hence restart position not advancing in the ISCDC) sometime is a concern because when ISCDC is to be restarted for som...