您是否每次都需要一个IndexReader和IndexSearcher的新实例? [英] Do you need a new instance of IndexReader and IndexSearcher every time?

问题描述

在一个Web应用程序中，整个应用程序有一个IndexReader和一个分别的IndexSearcher.

In a web application, I'm having one IndexReader and one respective IndexSearcher for the whole application.

文档说它们是线程安全的，这样就可以了，但是如果基础索引发生了变化(例如IndexWriter进行了更改)，它应该可以正常工作吗?

The documentation says they are thread-safe, so that's ok, but is it supposed to work properly if the underlying index changes (e.g. an IndexWriter makes changes)?

推荐答案

是的，您需要重新打开阅读器.

Yes, you need to reopen the reader.

使用 SearcherManager 来自动更新阅读器，调用进行更改后> maybeRefresh .

Use the SearcherManager to automatically update the reader, calling maybeRefresh when you've made changes.

下面的Scala代码示例:

Samples of Scala code below:

@volatile protected var LAST_SEARCHER_REFRESH = 0
protected lazy val SEARCHER_MANAGER = new SearcherManager (LUCENE_DIR, new SearcherFactory {
  override def newSearcher (reader: IndexReader): IndexSearcher = {new IndexSearcher (reader)}
})

...

if (LAST_SEARCHER_REFRESH != Time.relativeSeconds()) {LAST_SEARCHER_REFRESH = Time.relativeSeconds(); SEARCHER_MANAGER.maybeRefresh()}
val searcher = SEARCHER_MANAGER.acquire(); try {
  searcher.search (query, collector)
  ...
} finally {SEARCHER_MANAGER.release (searcher)}

有时候，您有时必须实现自己的缓存，例如 IndexSearcher描述有关如何操作的建议做到这一点(通过

Sometimes you'll have to implement your own caching though, like when you need to synchronize the IndexReader with TaxonomyReader. IndexSearcher description has recommendations about how to do that (there is a fast path via DirectoryReader.open(IndexWriter, applyAllDeletes) to make a new reader from a writer used to commit the changes).

这篇关于您是否每次都需要一个IndexReader和IndexSearcher的新实例?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！