Transaction recovery

Transaction recovery handles the following types of error:

• Errors in the application program

  This includes all situations in which the current transaction of the application program has to be rolled back, e.g. if the application program crashes, a deadlock occurs or the transaction is rolled back by the DML statement FINISH WITH CANCEL.

• Errors in the system

  This means all errors that occur in the DBH, e.g. a UDS/SQL system crash, a BS2000 system crash or a shortage of resources. File errors are not included in this category; these errors are handled using media recovery.

A prerequisite for using this type of recovery is that you have saved changes to your database using both the ALOG and the RLOG file.