Cube transaction logging

Optionally, a transaction log is maintained for specified cubes. This transaction log records every transaction made to an OLAP cube into a separate log file with the exception of cell note changes.

This log file can be used to restore changes to a cube in case the Database Worker was unable to save the cube before shutting down. A separate log file is maintained for each specified OLAP cube. It is named after the cube being logged and has a TRS extension. For example, SALES.TRS. The file is saved in the database directory.

The transaction file is maintained as long as the corresponding cube is not saved. If you issue a cube save command, or the cube is saved automatically, the transaction log is cleared and restarted. When a value writeback operation finishes successfully, one or more transaction log entries are recorded atomically in the log file. The transaction log stores the value written to the cube and the address of the cell to which the change was made.

In the event of a power failure, the log file is used by the Database Worker to restore the specified cubes. Upon initialization of the database, when a cube with an existing transaction log file is first loaded into memory, the Database Worker restores each transaction to its value prior to the power failure. A message appears at the Information level in the System Logs indicating that the transactions have been restored.

The transaction log can be enabled in the Edit Database dashboard on the properties of a cube in the "Security" section.