[SOLR-9510] child level facet exclusions

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.3, 8.0
• Component/s: Facet Module, faceting, query parsers
• Assignee: Mikhail Khludnev
• Reporter: Mikhail Khludnev
• Created: 14/Sep/16 09:31
• Updated: 05/Jun/20 21:41
• Resolved: 11/Mar/18 18:01

Description

Caveat SOLR-12275 bug in Solr 7.3

{!filters} as wells as filters local param in {!parent filters=...}... and {!child filters=..}... is broken in 7.3, workaround is adding cache=false as a local parameter. SOLR-12275 is fixed in Solr 7.4.

Challenge

• Since SOLR-5743 achieved block join child level facets with counts roll-up to parents, there is a demand for filter exclusions.

Context

• Then, it's worth to consider JSON Facets as an engine for this functionality rather than support a separate component.
• During a discussion in SOLR-8998 a solution for block join with child level exclusion has been found.

Proposal

It's proposed to provide a bit of syntax sugar to make it user friendly, believe it or not.

List of improvements

• introducing a local parameter filters for {!parent query parser referring to multiple filters queries via parameter name: {{ {!parent filters=$child.fq ..}

  ..&child.fq=color:Red&child.fq=size:XL}}
  these filters are intersected with a child query supplied as a subordinate clause.

• introducing {!filters param=$child.fq excludeTags=color v=$subq}&subq=text:word&child.fq= {!tag=color}color:Red&child.fq=size:XL it intersects a subordinate clause (here it's subq param, and the trick is to refer to the same query from {{ {!parent}

  }}), with multiple filters supplied via parameter name param=$child.fq, it also supports excludeTags.

Notes

Regarding the latter parser, the alternative approach might be to move into {{domain:

{..}

}} instruction of json facet. From the implementation perspective, it's desired to optimize with bitset processing, however I suppose it's might be deferred until some initial level of maturity.

Example

q={!parent which=type_s:book filters=$child.fq v=$childquery}&childquery=comment_t:good&child.fq={!tag=author}author_s:yonik&child.fq={!tag=stars}stars_i:(5 3)&wt=json&indent=on&json.facet={
comments_for_author:{
  type:query,
  q:"{!filters param=$child.fq excludeTags=author v=$childquery}",
  "//note":"author filter is excluded",
  domain:{
     blockChildren:"type_s:book",
     "//":"applying filters here might be more promising"
   }, facet:{
   authors:{
      type:terms,
      field:author_s,
      facet: {
          in_books: "unique(_root_)"
        }
    }
   }
} ,
comments_for_stars:{
  type:query,
 q:"{!filters param=$child.fq excludeTags=stars v=$childquery}",
  "//note":"stars_i filter is excluded",
  domain:{
     blockChildren:"type_s:book"
   }, facet:{
   stars:{
      type:terms,
      field:stars_i,
      facet: {
          in_books: "unique(_root_)"
        }
    }
  }
}
}

Votes? Opinions?

Issue Links

• is broken by: SOLR-12275 {!filters} are cached wrong
• is related to: SOLR-9683 include/exclude filters by tag
• is related to: SOLR-9681 add filter to any facet
• is related to: SOLR-9685 tag a query in JSON syntax
• relates to: SOLR-5743 Faceting with BlockJoin support
• relates to: SOLR-8998 JSON Facet API child roll-ups
• relates to: SOLR-14539 Query DSL: Introducing {!bool excludeTags=foo,bar}