The “.RUJ” files are “Run-Unit Journal” files, and they are critical to the automatic recovery mechanisms of Rdb and DBMS. Each processes that updates the database saves a pre-update copy of each modified record to this file. This allows a partially completed transaction to be rolled-back (undone) in the event of a deadlock, application or system failure.

Rdb and DBMS should automatically delete these files when the process unbinds from the database. At times, Rdb and DBMS does not delete these files – resulting in a “build-up” of obsolete RUJ files over time. If you have a directory full of these files, this can cause a serious performance problem.

Extreme caution should be used when deleting RUJ files. If you delete an RUJ file that is needed by Rdb or DBMS to rollback a partially completed transaction, the rollback will fail – leaving the database in an inconsistent state. This will cause Rdb or DBMS to abort all other users on the database with a  “RDMS-F-TERMINATE” or “DBM-F-TERMINATE” message. This is not good! The “official” recovery method is to restore the database from the last backup and then roll forward all completed transactions from the After Image Journal (AIJ) files.