Question

I want to get the information that is returned by this query from SolrNet:

http://localhost:8983/solr/terms?terms.fl=Title&terms.sort=index&terms.limit=10000&terms.mincount=10&version=2.2

Solr has support for specifying the terms parameters, but I don’t know how to retrieve the terms information. Executing a query goes to the select query handler, which throws an error. Here is what I have so far:

var solr = ServiceLocator.Current.GetInstance<ISolrOperations<ProductAdvertisementWidget>>();
int termLimit = 10000;
int minCount = 10;
var termParameters = new TermsParameters("Title");
termParameters.MinCount = minCount;
termParameters.Limit = termLimit;
termParameters.Sort = TermsSort.Index;            
var options = new QueryOptions()
      {
      Terms = termParameters,
      Rows = 0
      };

var queryOptions = new QueryOptions();
queryOptions.Terms = termParameters;
int lastResultCount = termLimit;

IEnumerable<KeyValuePair<string, int>> terms =
    solr.Query(new SolrQuery(""), options).Terms.FirstOrDefault(
    x=>x.Field == SolrFieldMappings.Name).Terms; 

SolrNet translates that into this query, which fails:

http://localhost:8983/solr/select?q=&terms.fl=Title&terms.sort=index&terms.limit=10000&terms.mincount=10&version=2.2

The error message is:

HTTP ERROR 500

Problem accessing /solr/select. Reason:

null

java.lang.NullPointerException at java.io.StringReader.(Unknown
Source) at
org.apache.lucene.queryParser.QueryParser.parse(QueryParser.java:203)
at
org.apache.solr.search.LuceneQParser.parse(LuceneQParserPlugin.java:80)
at org.apache.solr.search.QParser.getQuery(QParser.java:142) at
org.apache.solr.handler.component.QueryComponent.prepare(QueryComponent.java:81)
at
org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:173)
at
org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:129)
at org.apache.solr.core.SolrCore.execute(SolrCore.java:1368) at
org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:356)
at
org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:252)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:399)
at
org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at
org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at
org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
at
org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
at
org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at
org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326) at
org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at
org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:928)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549) at
org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212) at
org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) at
org.mortbay.jetty.bio.SocketConnector$Connection.run(SocketConnector.java:228)
at
org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582

)

Answer 1

This NullPointerException is a bug in Lucene, please report it. Lucene should not throw such a generic NullPointerException without any other information to help the user find the cause. Consider submitting a patch.

That said, you should not pass an empty query to Solr. Use SolrQuery.All with 0 rows instead if you only want terms information.

Also make sure you have the TermsComponent correctly configured in the default Solr request handler.