哪位高手见过此异常？？是关于lucene的异常java.io.IOException: background merge hit exception: _br:c1 _bs:c1 into _bt [optimize]

2008-11-12 16:31:20 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet insert threw exception
java.io.IOException: background merge hit exception: _br:c1 _bs:c1 into _bt [optimize]
at org.apache.lucene.index.IndexWriter.optimize(IndexWriter.java:1749)
at org.apache.lucene.index.IndexWriter.optimize(IndexWriter.java:1689)
at org.apache.lucene.index.IndexWriter.optimize(IndexWriter.java:1669)
at test1.IndexerTest1.index(IndexerTest1.java:28)
at testservlet.insert.doPost(insert.java:78)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
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:128)
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:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)