Through the Portal, you can define the number of days that data is retained before it is purged. At install time, these settings are configured to meet the requirements of your Experience Analytics solution.
Over time, the volume of web traffic and enterprise requirements may require more or less data retention in the database. Additional information on the effects of changing data retention for each type of retained data is listed in the following sections.
General effects of increasing data retention
- The size of the database grows. Depending on the type of data, this growth can be substantial, particularly for hourly data.
- The increased volume of data negatively impacts the speed of data aggregation for the Data Collector. The larger indexes on the tables result in increased lookup and update times to the data tables.
- The performance of Portal reporting is negatively impacted for the same reasons that data aggregation is affected. Larger indexes cause longer lookups and query processing.
- Depending on the amount of RAM available on the server hosting the database, the increase in data may cause an increase in SQL Server paging. If the amount of data being accessed consumes all available RAM, SQL Server pages the data to disk, which results in slow query processing.
Decreasing the length of data retention results in the inverse of the above impacts. In some cases, reducing these values can significantly increase performance, especially if there are hardware or storage limitations.
Reporting data retention
The reporting data consists of data aggregated by time across all events and report groups. The size of the data depends on the number of events, their firing frequency, and the variation in values for and dimensions used in report groups.
For more complex and high volume systems, these stored data types can rapidly lead to a large volume of data. Properly setting the data retention settings is the best way to control the size of the Experience Analytics databases and ensure proper system performance.
Data retention is controlled by the settings found in the Data Retention section of the Experience Analytics CX Settings page.
System processing stats data retention
Individual components in the Experience Analytics system have access to a statistical logging function, which captures stats data as hits from the Experience Analytics pipeline for collection by the Data Collector. These statistical hits are then written directly to the database.