How to fix SolrException: QueryElevationComponent requires the schema to have a uniqueKeyField?

Question

I am setting up a solr built into tomcat. I can get the example running in tomcat no problem. I then try to change schema.xml to a very simple one and I get an error.

This is my schema.xml

<?xml version="1.0" encoding="UTF-8" ?>
<schema name="minimal" version="1.1">
<types>
<fieldType name="string" class="solr.StrField"/>
</types>
<fields>
<dynamicField name="*" type="string" indexed="true" stored="true"/>
</fields>
</schema>

This is the error I get on start up:

May 24, 2012 10:03:33 AM org.apache.solr.core.SolrCore close
INFO: []  CLOSING SolrCore org.apache.solr.core.SolrCore@666b581a
May 24, 2012 10:03:33 AM org.apache.solr.core.QuerySenderListener newSearcher
INFO: QuerySenderListener sending requests to Searcher@2a664d5f main
May 24, 2012 10:03:33 AM org.apache.solr.update.DirectUpdateHandler2 close
INFO: closing DirectUpdateHandler2{commits=0,autocommits=0,optimizes=0,rollbacks=0,expungeDeletes=0,docsPending=0,adds=0,deletesById=0,deletesByQuery=0,errors=0,cumulative_adds=0,cumulative_deletesById=0,cumulative_deletesByQuery=0,cumulative_errors=0}
May 24, 2012 10:03:33 AM org.apache.solr.update.DirectUpdateHandler2 close
INFO: closed DirectUpdateHandler2{commits=0,autocommits=0,optimizes=0,rollbacks=0,expungeDeletes=0,docsPending=0,adds=0,deletesById=0,deletesByQuery=0,errors=0,cumulative_adds=0,cumulative_deletesById=0,cumulative_deletesByQuery=0,cumulative_errors=0}
May 24, 2012 10:03:33 AM org.apache.solr.common.SolrException log
SEVERE: java.lang.NullPointerException
    at org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:164)
    at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:129)
    at org.apache.solr.core.SolrCore.execute(SolrCore.java:1376)
    at org.apache.solr.core.QuerySenderListener.newSearcher(QuerySenderListener.java:59)
    at org.apache.solr.core.SolrCore$3.call(SolrCore.java:1182)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

May 24, 2012 10:03:33 AM org.apache.solr.core.SolrCore execute
INFO: [] webapp=null path=null params={event=firstSearcher&q=static+firstSearcher+warming+in+solrconfig.xml} status=500 QTime=12 
May 24, 2012 10:03:33 AM org.apache.solr.core.QuerySenderListener newSearcher
INFO: QuerySenderListener done.
May 24, 2012 10:03:33 AM org.apache.solr.handler.component.SpellCheckComponent$SpellCheckerListener newSearcher
INFO: Loading spell index for spellchecker: default
May 24, 2012 10:03:33 AM org.apache.solr.core.SolrCore registerSearcher
INFO: [] Registered new searcher Searcher@2a664d5f main
May 24, 2012 10:03:33 AM org.apache.solr.core.SolrCore closeSearcher
INFO: [] Closing main searcher on request.
May 24, 2012 10:03:33 AM org.apache.solr.search.SolrIndexSearcher close
INFO: Closing Searcher@2a664d5f main
    fieldValueCache{lookups=0,hits=0,hitratio=0.00,inserts=0,evictions=0,size=0,warmupTime=0,cumulative_lookups=0,cumulative_hits=0,cumulative_hitratio=0.00,cumulative_inserts=0,cumulative_evictions=0}
    filterCache{lookups=0,hits=0,hitratio=0.00,inserts=0,evictions=0,size=0,warmupTime=0,cumulative_lookups=0,cumulative_hits=0,cumulative_hitratio=0.00,cumulative_inserts=0,cumulative_evictions=0}
    queryResultCache{lookups=0,hits=0,hitratio=0.00,inserts=0,evictions=0,size=0,warmupTime=0,cumulative_lookups=0,cumulative_hits=0,cumulative_hitratio=0.00,cumulative_inserts=0,cumulative_evictions=0}
    documentCache{lookups=0,hits=0,hitratio=0.00,inserts=0,evictions=0,size=0,warmupTime=0,cumulative_lookups=0,cumulative_hits=0,cumulative_hitratio=0.00,cumulative_inserts=0,cumulative_evictions=0}
May 24, 2012 10:03:33 AM org.apache.solr.common.SolrException log
SEVERE: org.apache.solr.common.SolrException
    at org.apache.solr.core.SolrCore.<init>(SolrCore.java:600)
    at org.apache.solr.core.CoreContainer.create(CoreContainer.java:483)
    at org.apache.solr.core.CoreContainer.load(CoreContainer.java:335)
    at org.apache.solr.core.CoreContainer.load(CoreContainer.java:219)
    at org.apache.solr.core.CoreContainer$Initializer.initialize(CoreContainer.java:161)
    at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:96)
    at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:277)
    at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:258)
    at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:382)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:103)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4638)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5294)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:649)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1585)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)
Caused by: org.apache.solr.common.SolrException: QueryElevationComponent requires the schema to have a uniqueKeyField.
    at org.apache.solr.handler.component.QueryElevationComponent.inform(QueryElevationComponent.java:160)
    at org.apache.solr.core.SolrResourceLoader.inform(SolrResourceLoader.java:527)
    at org.apache.solr.core.SolrCore.<init>(SolrCore.java:594)
    ... 23 more

May 24, 2012 10:03:33 AM org.apache.solr.servlet.SolrDispatchFilter init
SEVERE: Could not start Solr. Check solr/home property and the logs
org.apache.solr.common.SolrException: No cores were created, please check the logs for errors
    at org.apache.solr.core.CoreContainer$Initializer.initialize(CoreContainer.java:172)
    at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:96)
    at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:277)
    at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:258)
    at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:382)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:103)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4638)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5294)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:649)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1585)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

May 24, 2012 10:03:33 AM org.apache.solr.common.SolrException log
SEVERE: org.apache.solr.common.SolrException: No cores were created, please check the logs for errors
    at org.apache.solr.core.CoreContainer$Initializer.initialize(CoreContainer.java:172)
    at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:96)
    at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:277)
    at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:258)
    at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:382)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:103)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4638)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5294)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:649)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1585)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

Your help is much appreciated.

Answer 1

I think the answer is in the stack trace you provided:

Caused by: org.apache.solr.common.SolrException: QueryElevationComponent requires the schema to have a uniqueKeyField.

The example schema you've supplied doesn't have a UniqueKeyField defined

for example:

<uniqueKey>[Put name of field here]</uniqueKey>

However, as your schema doesn't define any fixed fields, you'll have to add one first.