Sorted Federation Strategy
- Shaun Morris
- Brad Hards
Description
The Sorted Federation Strategy is the default Federation Strategy and is based on sorting metacards by the sorting parameter specified in the federated query.
The possible sorting values are:
- metacard's effective date/time
- temporal data in the query result
- distance data in the query result
- relevance of the query result
The supported sorting orders are Ascending or Descending.
The default sorting value/order automatically used is Relevance Descending.
The SortedFederationStrategy expects the results returned from the Sources to be sorted based on whatever sorting criteria were specified. If a metadata record in the query results contains null values for the sorting criteria elements, the SortedFederationStrategy expects that result to come at the end of the result list.
Configuration
The Sorted Federation Strategy configuration can be found in the webconsole under Configuration -> Catalog Sorted Federation Strategy.
| Property | Type | Description | Default Value | Required |
|---|---|---|---|---|
maxStartIndex | Integer | The maximum query offset number (any number from 1 to unlimited). Setting the number too high would allow offset queries that could result in an out of memory error because the DDF will cycle through all records in memory. Things to consider when setting this value are:
| 50000 | yes |
| Managed Service PID | ddf.catalog.SortedFederationStrategy |
|---|---|
| Managed Service Factory PID | N/A |