有趣的Lucene.net异常

Question

根据这或这，我通过多个线程使用相同的索引搜索器。但是当我从FsDirectory转到MMapDirectory时，我发现了一些有趣的例外。

这项工作做得很好：

static void Main(string[] args) 
{
    DirectoryInfo directoryInfo = new DirectoryInfo(@"C:\Users\Tams\Desktop\new\");
    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));
        }
    }
}

但有了这个：

static void Main(string[] args)
 {
    DirectoryInfo directoryInfo = new DirectoryInfo(@"C:\Users\Tams\Desktop\new\");
    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, 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));
        }
    }
}

我有很多例外，比如：

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.Net\FullRepo\trunk\src\core\Index\FieldInfos.cs:line 378   
at Lucene.Net.Index.FieldsReader.Doc(Int32 n, FieldSelector fieldSelector) 
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\FieldsReader.cs:line 234  
at Lucene.Net.Index.SegmentReader.Document(Int32 n, FieldSelector fieldSelector)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\SegmentReader.cs:line 1193
at Lucene.Net.Index.DirectoryReader.Document(Int32 n, FieldSelector fieldSelector)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\DirectoryReader.cs:line 686
at Lucene.Net.Index.IndexReader.Document(Int32 n) 
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\IndexReader.cs:line 732
at Lucene.Net.Search.IndexSearcher.Doc(Int32 i)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Search\IndexSearcher.cs:line 162
at PerformanceTest.Program.Search(IndexSearcher reader, Int32 times)
    in c:\Users\Tams\Documents\Visual Studio 2012\Projects\BookCatalog\PerformanceTest\Program.cs:line 28
at PerformanceTest.Program.<>c__DisplayClass2.<Main>b__0()
    in c:\Users\Tams\Documents\Visual Studio 2012\Projects\BookCatalog\PerformanceTest\Program.cs:line 43
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.Execute()

或

System.IO.IOException: read past EOF
at Lucene.Net.Store.BufferedIndexInput.Refill()
    in d:\Lucene.Net\FullRepo\trunk\src\core\Store\BufferedIndexInput.cs:line 179
at Lucene.Net.Store.BufferedIndexInput.ReadByte()
    in d:\Lucene.Net\FullRepo\trunk\src\core\Store\BufferedIndexInput.cs:line 41
at Lucene.Net.Store.IndexInput.ReadVInt()
    in d:\Lucene.Net\FullRepo\trunk\src\core\Store\IndexInput.cs:line 88   
at Lucene.Net.Index.FieldsReader.Doc(Int32 n, FieldSelector fieldSelector)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\FieldsReader.cs:line 230  
at Lucene.Net.Index.SegmentReader.Document(Int32 n, FieldSelector fieldSelector)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\SegmentReader.cs:line 1193
at Lucene.Net.Index.DirectoryReader.Document(Int32 n, FieldSelector fieldSelector)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\DirectoryReader.cs:line 686
at Lucene.Net.Index.IndexReader.Document(Int32 n)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Index\IndexReader.cs:line 732   
at Lucene.Net.Search.IndexSearcher.Doc(Int32 i)
    in d:\Lucene.Net\FullRepo\trunk\src\core\Search\IndexSearcher.cs:line 162
at PerformanceTest.Program.Search(IndexSearcher reader, Int32 times)
    in c:\Users\Tams\Documents\Visual Studio 2012\Projects\BookCatalog\PerformanceTest\Program.cs:line 28
at PerformanceTest.Program.<>c__DisplayClass2.<Main>b__0()
    in c:\Users\Tams\Documents\Visual Studio 2012\Projects\BookCatalog\PerformanceTest\Program.cs:line 43
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.Execute()

最后一段代码运行良好，将concurrentTaskCount变量设置为1。

我是不是遗漏了什么？我搞不懂那是什么。

实际上，我没有这条路

d:\Lucene.Net\FullRepo\trunk\src\core\Store\BufferedIndexInput.cs

我连一个字母"d“的车都没有

Answer 1

MMapDirectory的来源显示这个类不像预期的那样使用内存映射文件。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查找和读取时问题的原因。

您可以通过将基于内存的索引加载到RAMDirectory中来获得它。这通过了你的测试。(但它做的是MMapDirectory当前的工作，而不一定是您期望它所做的.)

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