[SOLR-5720] Add ExpandComponent to expand results collapsed by the CollapsingQParserPlugin

• Type: New Feature
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 4.8, 6.0
• Assignee: Joel Bernstein
• Reporter: Joel Bernstein
• Created: 13/Feb/14 00:33
• Updated: 08/Oct/19 17:51
• Resolved: 01/Apr/14 20:20

Description

This ticket introduces a new search component called the ExpandComponent. The expand component expands a single page of results collapsed by the CollapsingQParserPlugin.

Sample syntax:

q=*:*&fq={!collapse field=fieldA}&expand=true&expand.sort=fieldB+asc&expand.rows=10

In the above query the results are collapsed on "fieldA" with the CollapsingQParserPlugin. The expand component expands the current page of collapsed results.

The initial implementation of the ExpandComponent takes three parameters:

expand=true (Turns on the ExpandComponent)
expand.sort=fieldB+asc,fieldC+desc (Sorts the documents based on a sort spec. If none is specified the documents are sorted by relevance based on the main query.)
expand.rows=10 (Sets the numbers of rows that groups are expanded to).

Issue Links

• breaks: SOLR-6759 ExpandComponent does not call finish() on DelegatingCollectors
• is related to: SOLR-5027 Field Collapsing PostFilter
• is related to: SOLR-5829 Allow ExpandComponent to accept query and filter query parameters
• is related to: SOLR-6690 Highlight expanded results
• relates to: SOLR-5773 CollapsingQParserPlugin should make elevated documents the group head