[SOLR-7306] Add percentiles to Facet Module

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.1
• Assignee: Yonik Seeley
• Reporter: Yonik Seeley
• Created: 25/Mar/15 14:14
• Updated: 15/Apr/15 00:30
• Resolved: 25/Mar/15 18:10

Description

Use Ted Dunnings t-digest to add distributed percentile support to the new Facet Module (aka "JSON Facets").

// single percentile over complete doc set
json.facet={ median : 'percentile(my_field,50)' }

// calculate multiple percentiles of a function
json.facet={multi:'percentile( mul(f1,f2), 1,10,50,90,99)' }

// calculate the median of each facet bucket and sort by that value
json.facet={categories:{terms:{
  field:cat ,
  sort:'median desc' ,
  facet : {
    median : 'percentile(myfield,50)' ,
    otherstat : 'sum(something_else)'
  }
}}}