CDC agents that support transactions can eliminate uncommitted changes from the stream service Most CDC agents support transactions. The reference section for each CDC agent indicates whether the agent supports transactions.
The following CDC agents support transactions:
  • DB2 and DB2/400
  • VSAM Batch
  • Adabas (all Adabas agents)
  • Oracle
  • Enscribe
  • SQL/MP

When a CDC agent handles a transaction it reads the change record and then:
  • If the record is from a new transaction it creates an in memory transaction record cache for Txn-ID
  • If the record is a DML record, then it is added to the appropriate transaction record cache by the Txn-ID
  • If there was a Rollback, it deletes the Txn-ID transaction cache
  • If there was a Commit, it distributes the Txn-ID transaction records to the various change files
  • It the transactions is idled for too long it is timed out

    This is written to a special Txn-ID.txe file