Fast Distinct Values
Composer connectors that support fast distinct values can efficiently return distinct values for a field. This functionality optimizes the retrieval of distinct (unique) values in large numbers of records. If a connector supports this feature, the Filter dialog is populated with distinct values for an attribute directly from the data source, without the need to refresh the data and without retrieving or storing the distinct values in Composer's metadata. For example, Elasticsearch keeps lists of distinct values at the ready. Features such as these make fast distinct values possible for your connector.
There is no metric that defines “fast”. This value is based on the judgment of the developer.
When custom ranges or list values are requested for a field, full data scans are not performed.
For most connectors, this feature can be safely left disabled without impact.
Support for this feature by Composer connectors is shown in the following table.
Key:Y - Supported; N - Not Supported; N/A - not applicable
|Apache Phoenix Query Server (QS)||N/A|
|Microsoft SQL Server||N/A|
|Real Time Sales||N/A|