java - 如何安全地关闭 IndexReader？

Question

我的问题很简单，当用IndexReader.openIfChanged(reader)替换掉之前的reader时，如何安全的关闭oldReader？

代码如下:(使用 Lucene 3.5)

IndexReader newReader=IndexReader.openIfChanged(reader);
if(newReader!=null){
    IndexReader oldReader=reader;
    IndexSearcher oldSearcher=searcher;

    reader=newReader;
    searcher=new IndexSearcher(newReader);

    oldSearcher.close();
    oldReader.close();//or oldReader.decRef(),result is the same
}

这段代码在守护线程中，每5秒运行一次

IndexReader 实例(reader 对象)是全局唯一的

由于此更改，我得到一个异常(exception):

org.apache.lucene.store.AlreadyClosedException: this IndexReader is closed
    at org.apache.lucene.index.IndexReader.ensureOpen(IndexReader.java:297)
    at org.apache.lucene.index.IndexReader.getSequentialSubReaders(IndexReader.java:1622)
    at org.apache.lucene.search.TermQuery$TermWeight.scorer(TermQuery.java:98)
    at org.apache.lucene.search.BooleanQuery$BooleanWeight.scorer(BooleanQuery.java:298)
    at org.apache.lucene.search.BooleanQuery$BooleanWeight.scorer(BooleanQuery.java:298)
    at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:577)
    at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:517)
    at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:487)
    at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:400)
    at org.zenofo.index.IndexManager.query(IndexManager.java:392)
    ...

IndexManager.java:392 使用reader对象(IndexReader实例，全局唯一)

IndexManager.query方法有大量并发请求，所有请求使用一个全局唯一的IndexReader实例(reader对象)

我需要关闭 oldReader 只是因为:

• Too many open files in Lucene Indexing when number of usersincrease
• Lucene Wiki:Too many open files

引用:

• API-IndexReader
• API-IndexSearcher

我该如何解决这个问题？

Answer 1

查看 NRTManager 和 SearcherManager。您真的不必自己处理这个问题。