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Digy commented on LUCENENET-358: -------------------------------- New CloseableThreadLocal implementation committed to 2.9.4g branch DIGY > CloseableThreadLocal memory leak in LocalDataStoreSlot (with workaround) > ------------------------------------------------------------------------- > > Key: LUCENENET-358 > URL: https://issues.apache.org/jira/browse/LUCENENET-358 > Project: Lucene.Net > Issue Type: Bug > Affects Versions: Lucene.Net 2.9.2, Lucene.Net 2.9.4, Lucene.Net 2.9.4g > Environment: Microsoft WIndows Server 2008 Enterprise x64. SP2. > .NET Framework 4.0 > Reporter: Rezgar Cadro > Assignee: Digy > Priority: Critical > Labels: "memory, CloseableThreadLocal, LocalDataStoreSlot, leak" > Fix For: Lucene.Net 2.9.4, Lucene.Net 2.9.4g > > Attachments: CloseableThreadLocal MemoryLeak.patch, > CloseableThreadLocal.diff, CloseableThreadLocal.diff, > CloseableThreadLocal.patch, TestMemLeakage.zip > > > Recently we have been suffering from a severe memory leak when executing > intense open/close operations on IndexSearcher and IndexModifier. > Memory profiling showed that memory is being held by LocalDataStore[] objects. > After some digging, the root of the problem has been found in > CloseableThreadLocal class: > private System.LocalDataStoreSlot t = > System.Threading.Thread.AllocateDataSlot(); > What we see is that every instantiated object of CloseableThreadLocal causes > new data slot allocation performed for every thread. > Thread.AllocateDataSlot() does not simply allocate a new slot, replacing an > old one, but enlarging an existing buffer in-thread, appending data to the > end of internal LocalDataStore[] collection, which causes a severe memory > leak . > As long as "t" variable is instantiated on every object creation, and (in > current class implementation) every object is used by a single thread, > replacing "private System.LocalDataStoreSlot t = > System.Threading.Thread.AllocateDataSlot();" with simple "private object > dataSlot;" and removing "hardRefs" Dictionary solves the problem and prevents > memory leak. > We have tried to implement the expected behavior by using [ThreadStatic] > attribute instead of LocalDataStoreSlot, but the attempt failed because of > unexpected exceptions being thrown. > Patch can be found at Lucene.Net repository under -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira