Maximum number of dimension values

For data storage purposes, each dimension can be assigned a maximum number of values to be captured per hour for each Discover Processing Server. For example, in a large website, a dimension that captures visited URLs may quickly exceed this value. Imposing a limit on the number of values ensures that a statistically meaningful sample of the available values is captured and reported.

Note: This value indicates the total number of instances of unique values permitted per hour for each Processing Server. For example, if your environment contains three Processing Servers and this value is set to 500, then a total of 1500 unique dimension values can be captured system-wide in an hour, with no more than 500 captured by an individual Processing Server.
  • It is possible to have specific values that are repeated in the hourly data set. For example, if the value shirt is appears 10 times in an hour for a dimension, it is recorded only once as a dimension value.
  • By default, this limit is set to 1000. It can be set a maximum value of 50000 values per hour.
  • Processed values include whitelisted values, which also count against this limit. Blacklisted values do not count. * If the actual number of captured values exceeds this limit for a given hour, the default value for the dimension is recorded. See Dimension default values.

Each hour, the counter of dimension values resets to zero for each Processing Server. See Value limits for list dimensions.

Global fact limit

As a safeguard, Discover also enforces a maximum number of facts that can be generated. For each event, this limit is tested each user-defined interval (Fact Limits - Check Interval (minutes)) for the preceding hour.

  • By default, the limit for number of facts that are recorded per hour for an event is set to 500, 000.
  • If this limit is exceeded, any associated scorecard or dashboard is disabled. The fact is also disabled and must be re-enabled through the Report Groups step of the Event Wizard. See Manage Events - Events tab.
  • See "Settings" in the Unica Discover Administration Manual.

Global dimension value limit

To prevent runaway growth of the number of values that are stored for dimension data, Discover enforces a global limit on the number of dimensions that are retained for any individual dimension. Periodically, the Data Collector scans the values that are stored in the database for each dimension and removes the oldest values that exceed the defined number of permitted values, which are based on the timestamps when the values were recorded.

  • Counts for dimension values that are trimmed in this manner are moved to the [others] category.
    Note: The global dimension value limit is not intended to replace effective management of dimension data. Dimensions that reach the global limit are trimmed back to the global limit. If new values are added, the trimming is repeated, which can significantly burden the system over time. Discover recommends converting all high-volume dimensions to whitelists. See Data Management for Dimensions.