java - Lucene 的 MultiSearcher 与 IndexSearcher 与 MultiReader

Question

我即将编写一个具有分布式索引的近实时搜索应用程序。现在我想知道在多个索引上实现搜索的正确方法是什么:

我已经阅读了有关 MultiSearcher 的信息，所以一种方法是:

IndexSearcher[] indexSearchers = new IndexSearcher[indexCount];

for (int i = 0; i < indexCount; i++) {
    File directory = new File(indexdir, String.valueOf(i));
    IndexWriter indexWriter = new IndexWriter(FSDirectory.open(directory), analyzer, IndexWriter.MaxFieldLength.LIMITED);

    IndexReader indexReader = indexWriter.getReader();
    indexSearchers[i] = new IndexSearcher(indexReader);
}

MultiSearcher searcher = new MultiSearcher(indexSearchers);

但据我所知，这也是可能的:

IndexReader[] indexReader = new IndexReader[indexCount];

for (int i = 0; i < indexCount; i++) {
    File directory = new File(indexdir, String.valueOf(i));
    IndexWriter indexWriter = new IndexWriter(FSDirectory.open(directory), analyzer, IndexWriter.MaxFieldLength.LIMITED);

    indexReader[i] = indexWriter.getReader();        
}

IndexSearcher searcher = new IndexSearcher(new MultiReader(indexReader));

这两种方法之间有什么显着差异吗？如果读取器没有数据，第二个会更容易处理，因为我可以调用 MultiReader.reopen() 而不是遍历所有 IndexReader，重新打开它们，而不是创建新的 IndexSearchers...

Answer 1

您应该使用第二个选项:http://lucene.apache.org/core/old_versioned_docs/versions/3_5_0/api/all/org/apache/lucene/search/MultiSearcher.html