[SOLR-11329] contrib/ltr FieldValueFeature is silently 0.0 for external file fields

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 6.6
• Component/s: contrib - LTR
• Assignee: Unassigned
• Reporter: Christine Poerschke
• Created: 06/Sep/17 09:06
• Updated: 06/Sep/17 09:06

Description

By observation

{
  "name" : "popularityScoreAsFieldValueFeature",
  "class" : "org.apache.solr.ltr.feature.FieldValueFeature",
  "params" : { "field" : "popularity_score" }
}

returns a score of 0.0 for external file fields e.g.

<fieldType name="id2float" keyField="handle" defVal="0" class="solr.ExternalFileField" valType="float" />
<field name="popularity_score"  type="id2float" />

is schema content for the field.

In comparison (and as a workaround of sorts)

{
  "name" : "popularityScoreAsSolrFeature",
  "class" : "org.apache.solr.ltr.feature.SolrFeature",
  "params" : { "q" : "{!func}field(popularity_score)" }
}

returns the correct value.

The FieldValueFeature javadocs mention no restrictions re: fields needing to be non-external (or stored or indexed or whatever).

---

Improvements that could be made under this ticket:

• extend the javadocs to clarify what is and what is not supported
• add (further) test cases for not supported scenarios
• maybe: add support for external file fields
• maybe: throw an exception or noisely log (instead of silently returning 0.0) in not supported scenarios