c# – 有趣的Lucene.net异常

发布时间：2020-12-15 06:24:38 所属栏目：百科来源：网络整理

导读：根据 this或 this,我用多个线程使用相同的indexsearcher.但是当我从FsDirectory切换到MMapDirectory时,我有一些有趣的例外. 这个工作很好： static void Main(string[] args) { DirectoryInfo directoryInfo = new DirectoryInfo(@"C:UsersTamsDesktopne

根据 this或 this,我用多个线程使用相同的indexsearcher.但是当我从FsDirectory切换到MMapDirectory时,我有一些有趣的例外.

这个工作很好：

static void Main(string[] args) 
{
    DirectoryInfo directoryInfo = new DirectoryInfo(@"C:UsersTamsDesktopnew");
    var directory = FSDirectory.Open(directoryInfo);
    var indexSearcher = new IndexSearcher(directory);

    const int times = 100;
    const int concurrentTaskCount = 5;
    var task = new Task[concurrentTaskCount];
    for (int i = 0; i < concurrentTaskCount; i++) 
    {
        task[i] = new Task(() => Search(indexSearcher,times));
        task[i].Start();
    }

    Task.WaitAll(task);
}

static void Search(IndexSearcher reader,int times) 
{
    List<Document> docs = new List<Document>(10000);
    for (int i = 0; i < times; i++) 
    {
        var q = new TermQuery(new Term("title","volume"));
        foreach (var scoreDoc in reader.Search(q,100).ScoreDocs)
        {
            docs.Add(reader.Doc(scoreDoc.Doc));
        }
    }
}

但是用这个：

static void Main(string[] args)
 {
    DirectoryInfo directoryInfo = new DirectoryInfo(@"C:UsersTamsDesktopnew");
    var directory = new MMapDirectory(directoryInfo); // CHANGED
    var indexSearcher = new IndexSearcher(directory);

    const int times = 100;
    const int concurrentTaskCount = 5;
    var task = new Task[concurrentTaskCount];
    for (int i = 0; i < concurrentTaskCount; i++)
    {
        task[i] = new Task(() => Search(indexSearcher,int times)
 {
    List<Document> docs = new List<Document>(10000);
    for (int i = 0; i < times; i++) 
   {
        var q = new TermQuery(new Term("title",100).ScoreDocs)
        {
            docs.Add(reader.Doc(scoreDoc.Doc));
        }
    }
}

我得到各种异常,如：

System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative 
                                    and less than the size of the collection.
Parameter name: index
at System.ThrowHelper.ThrowArgumentOutOfRangeException()
at System.Collections.Generic.List`1.get_Item(Int32 index)
at Lucene.Net.Index.FieldInfos.FieldInfo(Int32 fieldNumber)
    in d:Lucene.NetFullRepotrunksrccoreIndexFieldInfos.cs:line 378   
at Lucene.Net.Index.FieldsReader.Doc(Int32 n,FieldSelector fieldSelector) 
    in d:Lucene.NetFullRepotrunksrccoreIndexFieldsReader.cs:line 234  
at Lucene.Net.Index.SegmentReader.Document(Int32 n,FieldSelector fieldSelector)
    in d:Lucene.NetFullRepotrunksrccoreIndexSegmentReader.cs:line 1193
at Lucene.Net.Index.DirectoryReader.Document(Int32 n,FieldSelector fieldSelector)
    in d:Lucene.NetFullRepotrunksrccoreIndexDirectoryReader.cs:line 686
at Lucene.Net.Index.IndexReader.Document(Int32 n) 
    in d:Lucene.NetFullRepotrunksrccoreIndexIndexReader.cs:line 732
at Lucene.Net.Search.IndexSearcher.Doc(Int32 i)
    in d:Lucene.NetFullRepotrunksrccoreSearchIndexSearcher.cs:line 162
at PerformanceTest.Program.Search(IndexSearcher reader,Int32 times)
    in c:UsersTamsDocumentsVisual Studio 2012ProjectsBookCatalogPerformanceTestProgram.cs:line 28
at PerformanceTest.Program.<>c__DisplayClass2.<Main>b__0()
    in c:UsersTamsDocumentsVisual Studio 2012ProjectsBookCatalogPerformanceTestProgram.cs:line 43
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.Execute()

要么

System.IO.IOException: read past EOF
at Lucene.Net.Store.BufferedIndexInput.Refill()
    in d:Lucene.NetFullRepotrunksrccoreStoreBufferedIndexInput.cs:line 179
at Lucene.Net.Store.BufferedIndexInput.ReadByte()
    in d:Lucene.NetFullRepotrunksrccoreStoreBufferedIndexInput.cs:line 41
at Lucene.Net.Store.IndexInput.ReadVInt()
    in d:Lucene.NetFullRepotrunksrccoreStoreIndexInput.cs:line 88   
at Lucene.Net.Index.FieldsReader.Doc(Int32 n,FieldSelector fieldSelector)
    in d:Lucene.NetFullRepotrunksrccoreIndexFieldsReader.cs:line 230  
at Lucene.Net.Index.SegmentReader.Document(Int32 n,FieldSelector fieldSelector)
    in d:Lucene.NetFullRepotrunksrccoreIndexDirectoryReader.cs:line 686
at Lucene.Net.Index.IndexReader.Document(Int32 n)
    in d:Lucene.NetFullRepotrunksrccoreIndexIndexReader.cs:line 732   
at Lucene.Net.Search.IndexSearcher.Doc(Int32 i)
    in d:Lucene.NetFullRepotrunksrccoreSearchIndexSearcher.cs:line 162
at PerformanceTest.Program.Search(IndexSearcher reader,Int32 times)
    in c:UsersTamsDocumentsVisual Studio 2012ProjectsBookCatalogPerformanceTestProgram.cs:line 28
at PerformanceTest.Program.<>c__DisplayClass2.<Main>b__0()
    in c:UsersTamsDocumentsVisual Studio 2012ProjectsBookCatalogPerformanceTestProgram.cs:line 43
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.Execute()

最后一个代码工作正常,将concurrentTaskCount变量设置为1.

我错过了什么吗？我不明白是什么

其实我没有道路

d:Lucene.NetFullRepotrunksrccoreStoreBufferedIndexInput.cs

我甚至没有一个驱动器用字母“d”

解决方法

source for MMapDirectory显示,这个类没有按预期使用 memory-mapped files.它使用MemoryStream对象将所有索引文件加载到内存中,我猜这些流是不同线程寻找和读取时的问题的原因.

您可以通过将其加载到RAMDirectory中来获取基于内存的索引.这通过你的测试. (但是它是MMapDirectory目前所做的,不一定是你期望做的…)

var fsDirectory = FSDirectory.Open(directoryInfo);
var directory = new RAMDirectory(fsDirectory);

（编辑：李大同）

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