today i build up an Solr Cloud System with 3 nodes, 3 shards and 3 replications. After that I switched the application in order to use the new SolrCloud System instead the old one (singe instance).
While most of the features works fine, i found out that there are problems with field collapsing (or grouping).
Looking at the Solr documentation i don't find any informations about solrCloud and field collapsing problems.
Playing around with that feature in found out, that grouping with an group.field= works while group.query= generates an error.
For example
http://localhost:9080/solr/archive/select/?group.limit=10&rows=10&group.query=car&group=true
results in:
<lst name="error">
<str name="trace">java.lang.NullPointerException
at org.apache.solr.search.grouping.distributed.shardresultserializer.TopGroupsResultTransformer.transformToNative(TopGroupsResultTransformer.java:110)
at org.apache.solr.search.grouping.distributed.responseprocessor.TopGroupsShardResponseProcessor.process(TopGroupsShardResponseProcessor.java:80)
at org.apache.solr.handler.component.QueryComponent.handleGroupedResponses(QueryComponent.java:620)
at org.apache.solr.handler.component.QueryComponent.handleResponses(QueryComponent.java:603)
at org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:309)
at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:129)
at org.apache.solr.core.SolrCore.execute(SolrCore.java:1656)
at org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:454)
at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:275)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:736)
</str>
<int name="code">500</int>
</lst>
Is this an known bug in Solr 4 Beta? Or is group.field= not supported in SolrCloud?
Thank you.
Looks like it is being fixed in the next version of Solr