How to increase index.max_result_window from Liferay

Issue

• When the number of results is more than the default (10000) the following message appears on the Liferay portal logs:
  

  ERROR [http-nio-8080-exec-99][ElasticsearchIndexSearcher:165] java.lang.RuntimeException: org.elasticsearch.ElasticsearchStatusException: ElasticsearchStatusException[Elasticsearch exception [type=search_phase_execution_exception, reason=all shards failed]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Result window is too large, from + size must be less than or equal to: [10000] but was [11000]. See the scroll api for a more efficient way to request large data sets. This limit can be set by changing the [index.max_result_window] index level setting.]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Result window is too large, from + size must be less than or equal to: [10000] but was [11000]. See the scroll api for a more efficient way to request large data sets. This limit can be set by changing the [index.max_result_window] index level setting.]];
  
  java.lang.RuntimeException: org.elasticsearch.ElasticsearchStatusException: ElasticsearchStatusException[Elasticsearch exception [type=search_phase_execution_exception, reason=all shards failed]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Result window is too large, from + size must be less than or equal to: [10000] but was [11000]. See the scroll api for a more efficient way to request large data sets. This limit can be set by changing the [index.max_result_window] index level setting.]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Result window is too large, from + size must be less than or equal to: [10000] but was [11000]. See the scroll api for a more efficient way to request large data sets. This limit can be set by changing the [index.max_result_window] index level setting.]];

Environment

• Liferay DXP 7.2 (with Elasticsearch 7 connector installed)
• Liferay DXP 7.3
• Liferay DXP 7.4

Resolution

• Configuring `index.max_result_window` in Liferay DXP can be done by following the below:
  
  Add the below value under Menu --> Control Panel --> System Settings --> Search --> Elasticsearch 7 --> Additional Index Configurations
  

  { 
  
  "index.max_result_window" :x
  
  }

• `x` should be any value based on the portal. In the below image, it is 25000.
  
• Requires full reindex post configurational changes.
  Execute re-index the search indexes and spell check indexes from the Index Actions tab of Control Panel → Configuration → Search
  

Additional Information

• "Result window is too large" error on Elasticsearch 6