Question

Context:
A helper facade class is providing search methods for my application. As performance is not an issue, a new IndexSearcher is created for each query.

对于每个询问,都设立了一个新的搜索器:

File indexFile = new File(String absolutePathToIndex);
IndexSearcher searcher = new IndexSearcher(indexFile.getAbsolutePath(), true);

有时,我拿到<条码>已关闭的Exception,我不理解,因为没有分享搜索器物体。

Any ideas? Any best practice of how to open the index? Known issues? Thanks.

Stacktrace:

org.apache.lucene.store.AlreadyClosedException: this Directory is closed
        at org.apache.lucene.store.Directory.ensureOpen(Directory.java:251)
        at org.apache.lucene.store.FSDirectory.listAll(FSDirectory.java:530)
        at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:585)
        at org.apache.lucene.index.DirectoryReader.open(DirectoryReader.java:69)
        at org.apache.lucene.index.IndexReader.open(IndexReader.java:476)
        at org.apache.lucene.index.IndexReader.open(IndexReader.java:243)
        at org.apache.lucene.search.IndexSearcher.<init>(IndexSearcher.java:78)

Proposed Solution #1: the way to go?

Directory directory = FSDirectory.open(File indexFile);
IndexSearcher searcher = new IndexSearcher(directory, true);
...do the query...
searcher.close();

Question: the above code from solution #1 is created for EACH query. Is it necessary to close the directory too? Having checked the source code of Lucene 2.9.2, searcher.close() does not close the directory associated with the internal reader object.

Answer 1

The method which you call in this example is anyways deprecated. So maybe the use of the IndexSearcher(Directory path, boolean readOnly) shows up a different behavior.

You need to make sure that you dont close the Directory before every subsequent search finishes. So for example if you use this Directory multiple times and you reinstantiate the Searcher the other Searcher will be destroyed and probably close the Directory in the destructor.

因此,如果你已经使用未经解释的校长版本,则试图利用每名搜索者的新目录。

Answer 2

有了更新的卢塞尼语版本,我建议使用 rel=“nofollow noreferer”SearcherManager>。助手班最终躲藏了你不得不以其他方式实施的一致/锁定和生命周期步骤。

https://stackoverflow.com/users/359268/michael-mccandless” Mike McCandless , a Lucene Project comitter: http://blog.mikemccandless.com/09/lucenes-searchermanager-simplifies.html

Answer 3

If an error only happens under high concurrent load, it suggests that perhaps you have multiple threads attempting to close the directory Or trying to read from already closed directory. You haven t clarified whether absolutePath is a local variable inside a method, or an instance variable in an object which is getting reused by multiple threads -- so it s hard to guess.

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