我有一个Solr云（版本7.4），有2个节点（每个节点都有10 Gb SSD硬盘和256 Gb内存和50 Gb堆）和10个集合。今天我遇到了这个关于instagram_prime_archive集合的错误：

SolrIndexWriter was not closed prior to finalize(),​ indicates a bug -- POSSIBLE RESOURCE LEAK!!!

Error closing IndexWriter

null:org.apache.lucene.index.IndexNotFoundException: no segments* file found in LockValidatingDirectoryWrapper(NRTCachingDirectory(MMapDirectory@/home/solr/data/instagram_prime_archive_shard1_replica_n15/data/index.20190313041339667 lockFactory=org.apache.lucene.store.NativeFSLockFactory@6b54ef37; maxCacheMB=48.0 maxMergeSizeMB=4.0)): files: [_14jqg.cfe, _14jqg.cfs, _14jqg.si, _14jqg_xcc.liv, _17wrq.cfe, _17wrq.cfs, _17wrq.si, _17wrq_8im.liv, _19qhp.cfe, _19qhp.cfs, _19qhp.si, _19qhp_3ik.liv, _19wns.cfe, _19wns.cfs, _19wns.si, _19wns_1yp.liv, _1a0lx.cfe, _1a0lx.cfs, _1a0lx.si, _1a0lx_9a.liv, _1a3u8.cfe, _1a3u8.cfs, _1a3u8.si, _1a3u8_7g.liv, _1a5fe.cfe, _1a5fe.cfs, _1a5fe.si, _1a5fe_es.liv, _1a7fu.cfe, _1a7fu.cfs, _1a7fu.si, _1a7fu_bg.liv, _1a9oo.cfe, _1a9oo.cfs, _1a9oo.si, _1a9oo_cv.liv, _1abp0.cfe, _1abp0.cfs, _1abp0.si, _1abp0_3fk.liv, _1afn9.cfe, _1afn9.cfs, _1afn9.si, _1afn9_98.liv, _1ajhu.cfe, _1ajhu.cfs, _1ajhu.si, _1ajhu_6r.liv, _1an7f.cfe, _1an7f.cfs, _1an7f.si, _1an7f_6t.liv, _1ap2m.cfe, _1ap2m.cfs, _1ap2m.si, _1ap2m_87.liv, _1au5v.cfe, _1au5v.cfs, _1au5v.si, _1au5v_72.liv, _1audy.cfe, _1audy.cfs, _1audy.si, _1audy_m.liv, _1aup4.cfe, _1aup4.cfs, _1aup4.si, _1aup4_m.liv, _1auza.cfe, _1auza.cfs, _1auza.si, _1auza_x.liv, _1avb8.cfe, _1avb8.cfs, _1avb8.si, _1avb8_u.liv, _1avgt.cfe, _1avgt.cfs, _1avgt.si, _1avgt_k.liv, _1avhd.cfe, _1avhd.cfs, _1avhd.si, _1avhd_8c.liv, _1avq1.cfe, _1avq1.cfs, _1avq1.si, _1avq1_13.liv, _1azqq.cfe, _1azqq.cfs, _1azqq.si, _1azqq_4.liv, _1azwu.cfe, _1azwu.cfs, _1azwu.si, _1azwu_1r.liv, _1b08s.cfe, _1b08s.cfs, _1b08s.si, _1b08s_5.liv, _1b0kq.cfe, _1b0kq.cfs, _1b0kq.si, _1b0kq_m.liv, _1b0ni.cfe, _1b0ni.cfs, _1b0ni.si, _1b0qa.cfe, _1b0qa.cfs, _1b0qa.si, _1b0tm.cfe, _1b0tm.cfs, _1b0tm.si, _1b0tm_1.liv, _1b0zh.cfe, _1b0zh.cfs, _1b0zh.si, _1b100.cfe, _1b100.cfs, _1b100.si, _1b10k.cfe, _1b10k.cfs, _1b10k.si, _1b11e.cfe, _1b11e.cfs, _1b11e.si, _1b11p.cfe, _1b11p.cfs, _1b11p.si, _1b11y.cfe, _1b11y.cfs, _1b11y.si, _1b128.cfe, _1b128.cfs, _1b128.si, _1b12s.cfe, _1b12s.cfs, _1b12s.si, _1b132.cfe, _1b132.cfs, _1b132.si, _1b13c.cfe, _1b13c.cfs, _1b13c.si, _1b13d.dii, _1b13d.dim, _1b13d.fdt, _1b13d.fdx, _1b13d.fnm, _1b13d.nvd, _1b13d.nvm, _1b13d.si, _1b13d_Lucene50_0.doc, _1b13d_Lucene50_0.pos, _1b13d_Lucene50_0.tim, _1b13d_Lucene50_0.tip, _1b13d_Lucene70_0.dvd, _1b13d_Lucene70_0.dvm, _1b13e.dii, _1b13e.dim, _1b13e.fdt, _1b13e.fdx, _1b13e.fnm, _1b13e.nvd, _1b13e.nvm, _1b13e.si, _1b13e_Lucene50_0.doc, _1b13e_Lucene50_0.pos, _1b13e_Lucene50_0.tim, _1b13e_Lucene50_0.tip, _1b13e_Lucene70_0.dvd, _1b13e_Lucene70_0.dvm, _1b13f.dii, _1b13f.dim, _1b13f.fdt, _1b13f.fdx, _1b13f.fnm, _1b13f.nvd, _1b13f.nvm, _1b13f.si, _1b13f_Lucene50_0.doc, _1b13f_Lucene50_0.pos, _1b13f_Lucene50_0.tim, _1b13f_Lucene50_0.tip, _1b13f_Lucene70_0.dvd, _1b13f_Lucene70_0.dvm, _1b14j.dii, _1b14j.dim, _1b14j.fdt, _1b14j.fdx, _1b14j.fnm, _1b14j.nvd, _1b14j.nvm, _1b14j.si, _1b14j_2.liv, _1b14j_Lucene50_0.doc, _1b14j_Lucene50_0.pos, _1b14j_Lucene50_0.tim, _1b14j_Lucene50_0.tip, _1b14j_Lucene70_0.dvd, _1b14j_Lucene70_0.dvm, _1b14k.dii, _1b14k.dim, _1b14k.fdt, _1b14k.fdx, _1b14k.fnm, _1b14k.nvd, _1b14k.nvm, _1b14k.si, _1b14k_2.liv, _1b14k_Lucene50_0.doc, _1b14k_Lucene50_0.pos, _1b14k_Lucene50_0.tim, _1b14k_Lucene50_0.tip, _1b14k_Lucene70_0.dvd, _1b14k_Lucene70_0.dvm, _1b14q.dii, _1b14q.dim, _1b14q.fdt, _1b14q.fdx, _1b14q.fnm, _1b14q.nvd, _1b14q.nvm, _1b14q.si, _1b14q_2.liv, _1b14q_Lucene50_0.doc, _1b14q_Lucene50_0.pos, _1b14q_Lucene50_0.tim, _1b14q_Lucene50_0.tip, _1b14q_Lucene70_0.dvd, _1b14q_Lucene70_0.dvm, _pqyd.cfe, _pqyd.cfs, _pqyd.si, _pqyd_3bhn.liv, _r9bx.cfe, _r9bx.cfs, _r9bx.si, _r9bx_33sj.liv, write.lock]
at org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:832)
at org.apache.solr.update.SolrIndexWriter.<init>(SolrIndexWriter.java:124)
at org.apache.solr.update.SolrIndexWriter.create(SolrIndexWriter.java:97)
at org.apache.solr.update.DefaultSolrCoreState.createMainIndexWriter(DefaultSolrCoreState.java:257)
at org.apache.solr.update.DefaultSolrCoreState.getIndexWriter(DefaultSolrCoreState.java:131)
at org.apache.solr.update.DirectUpdateHandler2.doNormalUpdate(DirectUpdateHandler2.java:344)
at org.apache.solr.update.DirectUpdateHandler2.addDoc0(DirectUpdateHandler2.java:284)
at org.apache.solr.update.DirectUpdateHandler2.addDoc(DirectUpdateHandler2.java:234)
at org.apache.solr.update.processor.RunUpdateProcessor.processAdd(RunUpdateProcessorFactory.java:67)
at org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)
at org.apache.solr.update.processor.DistributedUpdateProcessor.doLocalAdd(DistributedUpdateProcessor.java:950)
at org.apache.solr.update.processor.DistributedUpdateProcessor.versionAdd(DistributedUpdateProcessor.java:1168)
at org.apache.solr.update.processor.DistributedUpdateProcessor.processAdd(DistributedUpdateProcessor.java:633)
at org.apache.solr.update.processor.LogUpdateProcessorFactory$LogUpdateProcessor.processAdd(LogUpdateProcessorFactory.java:103)
at org.apache.solr.update.processor.SignatureUpdateProcessorFactory$SignatureUpdateProcessor.processAdd(SignatureUpdateProcessorFactory.java:193)
at org.apache.solr.handler.loader.XMLLoader.processUpdate(XMLLoader.java:261)
at org.apache.solr.handler.loader.XMLLoader.load(XMLLoader.java:188)
at org.apache.solr.handler.UpdateRequestHandler$1.load(UpdateRequestHandler.java:97)
at org.apache.solr.handler.ContentStreamHandlerBase.handleRequestBody(ContentStreamHandlerBase.java:68)
at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:199)
at org.apache.solr.core.SolrCore.execute(SolrCore.java:2539)
at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:709)
at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:515)
at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:377)
at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:323)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1634)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1253)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1155)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:219)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.Server.handle(Server.java:531)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:760)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:678)
at java.lang.Thread.run(Thread.java:748)

我检查了htop，发现线程数是9897！！！x1c 0d1x
Thread Dump屏幕上也有很多线程：

这些错误的原因是什么？为什么要创建所有这些线程？
我的程式码是否有问题？