Cube transaction logging

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

This log file is used to automatically 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 the extension TRS. For example, SALES.TRS. The file is saved in the database directory.

The transaction file is created or updated when values of the corresponding cube change and is maintained as long as it is not saved. Upon a cube save or database save command, or when the cube is saved automatically, the corresponding transaction file is removed. 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 case of an irregular shutdown, the log files are 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 transactions saved prior to the irregular shutdown. 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.