Elasticsearch DynaRank Plugin

Overview

DynaRank Plugin provides a feature for Dynamic Ranking at a search time. You can change top N documents in the search result with your re-ordering algorithm. Elasticsearch has rescoring, but DynaRank is different as below:

• DynaRank's reranking is executed on requested node only, not on each shard.
• DynaRank uses a script language for reranking.

Version

Versions in Maven Repository

Issues/Questions

Please file an issue.

Installation

$ $ES_HOME/bin/elasticsearch-plugin install org.codelibs:elasticsearch-dynarank:7.6.0

Getting Started

Create Sample Data

Create "sample" index:

$ COUNT=1;while [ $COUNT -le 100 ] ; do curl -XPOST 'localhost:9200/sample/_doc/' -d "{\"message\":\"Hello $COUNT\",\"counter\":$COUNT}";COUNT=`expr $COUNT + 1`; done

100 documents are inserted. You can see 10 documents by an ascending order of "counter" field:

$ curl -XPOST "http://127.0.0.1:9200/sample/_search" -d'
{
   "query": {
      "match_all": {}
   },
   "sort": [
      {
         "counter": {
             "order": "asc"
         }
      }
   ]
}'

Enable Reranking

DynaRank plugin is enabled if your re-order script is set to the target index:

$ curl -s -XPUT -H 'Content-Type: application/json' "localhost:9200/sample/_settings" -d"
{
  \"index\" : {
    \"dynarank\":{
      \"script_sort\":{
        \"lang\": \"painless\",
        \"script\": \"def l=new ArrayList();for(def h:searchHits){l.add(h);}return l.stream().sorted((s1,s2)->s2.getSourceAsMap().get('counter')-s1.getSourceAsMap().get('counter')).toArray(n->new org.elasticsearch.search.SearchHit[n])\"
      },
      \"reorder_size\": 5
     }
  }
}"

This setting sorts top 5 documents (5 is given by reorder_size) by a descending order of "counter" field, and others are by an ascending order.

Disable Reranking

Set an empty value to index.dynarank.script_sort.script:

$ curl -s -XPUT -H 'Content-Type: application/json' "localhost:9200/sample/_settings" -d"
{
  \"index\" : {
    \"dynarank\":{
      \"script_sort\":{
        \"script\": \"\"
      }
     }
  }
}"

References

dynarank_diversity_sort Script Sort

DynaRank plugin provides a sort feature for a diversity problem. The sort script is dynarank_diversity_sort. The configuration is below:

curl -XPUT -H 'Content-Type: application/json' 'localhost:9200/sample/_settings' -d '
{
  "index" : {
    "dynarank":{
      "script_sort":{
        "lang":"dynarank_diversity_sort",
        "params":{
          "diversity_fields":["filedname1", "filedname2"],
          "diversity_thresholds":[0.95, 1]
        }
      },
      "reorder_size":100
     }
  }
}'

diversity_fields is fields for a diversity. diversity_thresholds is a threshold for a similarity of each document.