We are having an issue with searching a Lucene Index in Sitecore. Everything works fine for a while, and then, after what appears to be a random amount of time, we start getting the following error on every single search against the index:
System.ArgumentOutOfRangeException
Message: Non-negative number required.
Parameter name: capacity Source: mscorlib
at System.Collections.Hashtable..ctor(Int32 capacity, Single loadFactor)
at System.Collections.Hashtable.Clone()
at SupportClass.WeakHashTable.Clean()
at SupportClass.WeakHashTable.CleanIfNeeded()
at SupportClass.WeakHashTable.Add(Object key, Object value)
at Lucene.Net.Util.CloseableThreadLocal.Set(Object object)
at Lucene.Net.Index.TermInfosReader.GetThreadResources()
at Lucene.Net.Index.TermInfosReader.Get(Term term, Boolean useCache)
at Lucene.Net.Index.SegmentReader.DocFreq(Term t)
at Lucene.Net.Index.DirectoryReader.DocFreq(Term t)
at Lucene.Net.Search.Similarity.IdfExplain(Term term, Searcher searcher)
at Lucene.Net.Search.TermQuery.CreateWeight(Searcher searcher)
at Lucene.Net.Search.BooleanQuery.BooleanWeight..ctor(BooleanQuery enclosingInstance, Searcher searcher)
at Lucene.Net.Search.BooleanQuery.CreateWeight(Searcher searcher)
at Lucene.Net.Search.Query.Weight(Searcher searcher)
at Lucene.Net.Search.Hits..ctor(Searcher s, Query q, Filter f, Sort o)
at Lucene.Net.Search.Searcher.Search(Query query, Sort sort)
at scSearchContrib.Searcher.QueryRunner.RunQuery(Query query, Boolean showAllVersions, String sortField, Boolean reverse, Int32 start, Int32 end)
at scSearchContrib.Searcher.QueryRunner.GetItems(IEnumerable`1 parameters, Boolean showAllVersions, String sortField, Boolean reverse, Int32 start, Int32 end) at
Looking at the .Net code and Lucene.Net code being called (via ILSpy), I can't see how this would actually happen. Calling .Clone() on a hashtable shouldn't allow a negative number for the hashtable capacity to be passed in.
This has happened several times, on multiple servers in our farm, and restarting IIS resolves the issue. This leads me to believe that there is some sort of in-memory corruption happening, but I'm not sure what would cause this or how to figure out what is going on.
Sitecore support has a workaround for this for Sitecore 6.6. There are apparently some nasty thread-safety issues with the WeakHashTable class used in Lucene.NET 2.9.4. This issue is addressed in later versions of Lucene.NET and via the corresponding upgrades in Sitecore 7.
Try increasing number of worker threads for Sitecore by adding following setting to web.config
<setting name="MaxWorkerThreads" value="100"/>
来源：https://stackoverflow.com/questions/15906869/lucene-indexes-in-sitecore-getting-corrupted-argumentoutofrangeexception