You can check the Replication Server queues to determine which transactions are being processed or ignored, and to determine whether transactions are open, or not being committed.
To display information about SQM and SQT threads
Log in to the primary Replication Server and use the admin who, sqm command.
View the results to determine the number of duplicate messages being detected and ignored, and the number of blocks being written in the Replication Server stable queues.
In the primary Replication Server, use the admin who, sqt command.
View the results to find open transactions.
Replication Server Reference Manual for information about the admin who commands and results.