title: Why CPU usage close to reach to 100% when i use SOLR index the documents
body: <p>We use solr as out full text searcher. we use multi cores with solr and we have approximately 5 hundred million data. we batch update our index when reaches 1000 new record without commit them because we use auto commit in solr.In recently, when we batch post out new record, the cpu usage colse to 100%.
  I have dump the high cpu theads. most threads likes follows:</p>
  
  <pre><code>   java.lang.Thread.State: RUNNABLE
  at org.apache.lucene.search.ConjunctionTermScorer.doNext(ConjunctionTermScorer.java:64)
  at org.apache.lucene.search.ConjunctionTermScorer.nextDoc(ConjunctionTermScorer.java:95)
  at org.apache.lucene.search.Scorer.score(Scorer.java:63)
  at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:605)
  at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:297)
  at org.apache.solr.search.SolrIndexSearcher.getDocSetNC(SolrIndexSearcher.java:1060)
  at org.apache.solr.search.SolrIndexSearcher.getPositiveDocSet(SolrIndexSearcher.java:763)
  at org.apache.solr.search.SolrIndexSearcher.getProcessedFilter(SolrIndexSearcher.java:880)
  at org.apache.solr.search.SolrIndexSearcher.getDocListNC(SolrIndexSearcher.java:1337)
  at org.apache.solr.search.SolrIndexSearcher.getDocListC(SolrIndexSearcher.java:1304)
  at org.apache.solr.search.SolrIndexSearcher.search(SolrIndexSearcher.java:395)
  at org.apache.solr.handler.component.QueryComponent.process(QueryComponent.java:410)
  at org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:208)
  at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:135)
  at org.apache.solr.core.SolrCore.execute(SolrCore.java:1797)
  at org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:637)
  at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:343)
  at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:141)
  </code></pre>