## Usage Example

This processor pulls data from Solr collections. For its usage, Solr collections have to fulfil two requirements:

- The documents must include a date field containing the time when they were indexed. Such kind of field can be easily added to documents at indexing time e. g. using Solrs' UpdateRequestProcessor created by 'TimestampUpdateProcessorFactory'.
- The configuration of the Solr index (e. g. schema.xml or managed-schema) must define a uniqueKey field.

Backwards compatibility to configurations of the GetSolr processor used within releases of NiFi prior to 1.5 can be realized as follows:

- Find the file conf/.getSolr* within the prior NiFi installation.
- Open the file and copy the timestamp defined for 'LastEndDate'.
- Insert the timestamp into the field 'Initial Date Filter'.

Annotation: The value of property 'Solr Query' actually is not added to parameter 'q' but to parameter 'fq' for two reasons:

- Improving performance by leveraging Solrs' filter cache.
- Scoring is not required for the purpose of this processor as the sorting is fixed to 'DateField asc, IdField asc'