In Solr Cloud, is QueryElevationComponent mandatory in distributed collection?

Question

I have collection that is distributed over multiple solr cloud node. To disable uniqueKey in schema, I also disable QueryElevationComponent in solrconfig.xml.

<!--
  <searchComponent name="elevator" class="solr.QueryElevationComponent" >
    <str name="queryFieldType">string</str>
    <str name="config-file">elevate.xml</str>
  </searchComponent>
-->

Configuration works fine in undistributed collection (1 shard, 1 rf). But if number of shards*rf are greater than 1, problem occures. When I execute query to distributed collection, than solr throws below exception.

java.lang.NullPointerException at org.apache.solr.handler.component.QueryComponent.createMainQuery(QueryComponent.java:852) at org.apache.solr.handler.component.QueryComponent.regularDistributedProcess(QueryComponent.java:721) at org.apache.solr.handler.component.QueryComponent.distributedProcess(QueryComponent.java:674) at org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:345) at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:154)

Solr does not complain against indexing. Only querying is problem.

Answer 1

uniqueKey is required. as it will likely make routing in SolrCloud and document replacement in general fail.

Enable your uniqueKey in schema, if you are using solr in cloud mode.