[SOLR-7883] MoreLikeThis is incompatible with facets

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.2.1
• Fix Version/s: 9.1
• Component/s: faceting, MoreLikeThis

Environment

Arch Linux / OpenJDK 7.u85_2.6.1-1

• Assignee: Mikhail Khludnev
• Reporter: Thomas Seidl
• Created: 06/Aug/15 15:32
• Updated: 10/Mar/23 20:32
• Resolved: 15/Sep/22 15:30

Description

When using the MoreLikeThis request handler, it doesn't seem possible to also have facets. This worked in Solr 4, but seems to be broken now.

Example:
This works: ?qt=mlt&q=id:item1&mlt.fl=content
This doesn't: ?qt=mlt&q=id:item1&mlt.fl=content&facet=true

(Yes, you don't even need to specify any facet fields/ranges/queries. The q query just has to match an item.)
While the latter will actually return the same result set as the former, the HTTP status is 500 and the following error included in the response:

java.lang.NullPointerException
	at org.apache.solr.request.SimpleFacets.getHeatmapCounts(SimpleFacets.java:1753)
	at org.apache.solr.request.SimpleFacets.getFacetCounts(SimpleFacets.java:289)
	at org.apache.solr.handler.MoreLikeThisHandler.handleRequestBody(MoreLikeThisHandler.java:233)
	at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:143)
	at org.apache.solr.core.SolrCore.execute(SolrCore.java:2064)
	at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:654)
	at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:450)
	at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:227)
	at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:196)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
	at org.eclipse.jetty.server.Server.handle(Server.java:497)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:310)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
	at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
	at java.lang.Thread.run(Thread.java:745)

Issue Links

• causes: SOLR-16420 MoreLikeThis Content Query Parser
• relates to: SOLR-6248 MoreLikeThis Query Parser
• links to: GitHub Pull Request #1010
• links to: GitHub Pull Request #1015