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:

How much memory is allocated to the DDF Server
How many sites are being federated with.

50000

yes

Managed Service PID	`ddf.catalog.SortedFederationStrategy`
Managed Service Factory PID	N/A

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