To make informed and effective business intelligence decisions, you need to understand how the data on which you base those decisions changes over time.
You can track and display data changes to help you focus your analysis on key areas, and avoid wasting time exploring irrelevant data.
With data tracking, you can highlight the values that have changed since a previous refresh for any level of aggregation.
A document with data tracking activated retrieves two microcubes – one for the reference data set, and one for the current data set. The document compares the data in the two microcubes, and highlights the changes according to the formatting that you defined for the changes. Similarly, when a document contains calculations on the data set, it compares the calculations on each data set to display the changes.
A document with data tracking activated contains twice as much data as a document for which data tracking is not active. This means that the data tracking document can take up to three times as long to refresh.
Certain actions clear the document of the data stored in the microcubes or modify the data provider. When the document no longer contains the data, the data tracking function cannot compare the data sets and highlight the changes. Similarly, when the data provider changes, the current version of the document is not compatible with the reference version, so the changed data does not display.
Data tracking restrictions
If you change or purge a data provider, the report no longer displays changed data.
If the data provider is changed, the current version of the document is no longer compatible with the reference version. If the data is cleared, the old data no longer exists for comparison.
As a result, the following actions are incompatible with data tracking:
- Drill out of scope
- Query drill
- Deleting a query
- Any modification (including modifications to security rights) that changes the SQL generated by a data provider
- Purging the document
When you perform any of these actions, the data history of the document is cleared because the actions are incompatible with the display of changed data. For example, if you modify a query, the data in the document changes because of the modification. Any comparison between this data and old data generated from a different query is misleading.