Changelog

If the Enable Changelog option on the Database Settings dashboard is enabled, every cell change made by write and delete operations is logged to a file or to a relational data connection.

To administer the Changelog, select Dashboards > OLAP > Database Settings.

The extent to which you can configure the Changelog depends on the environment and application type:

  • On premises - custom applications

    Changelog is fully configurable for custom applications in on-premises environments.

  • Commercial applications

    For commercial applications in on-premises or cloud environments, you can only enable or disable Changelog. Some commercial applications do not support Changelog. In these cases, Changelog cannot be enabled.

  • Cloud - custom applications

    Changelog is not configurable for custom applications in the cloud.

What Changelog does

One example of a write operation is splashing. After splashing operations, the server writes one or more entries to the log file. Information about the operation, such as the value, is logged. In some cases, the values are not logged as delivered but as the computed end value. For example, if you have the value 1 in a specific cell and the delta operation applies a delta value of 2, then the server writes 3 as the value.

Information on the date, time, user name, cube name, cell address, original value, and new value is included.

These options determine which operations are to be logged:

  • All Cubes logs all client operations.
  • Cubes with Enabled Transaction Log logs only those operations that are also logged in the transaction log.
  • Log Splashing Operations logs splashing operations.

Changes to cell values are not logged if these events occur:

  • The entire cube is deleted.
  • The dimension element the cell belongs to is deleted.
  • The cell type is changed from:
    • S to N
    • N to C
    • S to C

These changes are not logged:

  • Attributes
  • Dimension
  • Cell comments
  • Cube structures
  • Configuration settings

Logging to file

The Alealog.txt file is created in the central database folder that is specified during configuration of the farm. It is tab-separated. Alealog.txt can be used if a database must be recreated or if users activities need to be monitored.
Caution: 
Unlike the transaction log file, this log file must be maintained manually. It will continue to grow and must be edited periodically to help to maintain stability of the environment.

The string cell limit is up to 1,000,000 bytes.

Logging to database

If the Enable Changelog and Log to Database options are selected, data cell changes are logged to Alealog.txt and to a relational data connection. The content of Alealog.txt is written to the relational server every 10 seconds and is automatically emptied if the insertion to the database is successful.

If there is no table with the name defined in the Table for Cell Changes option in the relational database, one is created when the first write operation happens.

A table for splashing operations is required for the Log Splashing Operations option. If there is no table with the name defined in the Table for Splasher Operations option, one is created when the first write operation happens.

We recommend that you delete Alealog.txt before you select the Log to Database option.

The regional settings of the OLAP database must be compatible with the regional settings of the relational data connection.

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