在使用 Lucene 建立索引期间搜索没有响应

Question

When I re-index the DB data of my application, and there is a search executed on the same time, the thread that runs the search is going to sleep until the re-indexing is done. I assume that the indexing methods are thread-safe in order to prevent change of the data while indexing. Is there any built in way in Lucene to make it responsive only for search (where the data is not being changed)? Or should I start thinking about something on my own? I'm running my application on a Tomcat server.

Thanks, Tomer

Answer 1

I assume that you are actually rebuilding the index (or reindexing everything from scratch, as opposed to reindexing individual documents). While the index is being rebuilt, you cannot perform the queries against it, because it's not in consistent state.

The simplest solution that is often used is to rebuild the index in the background (while still performing the queries against the old one) and then replace it with the fresh one.

If the problem you are facing is connected with frequent server crashes, it might be worthwhile to look at some more systematical approach like the one that is implemented for example in Zoie -- it records subsequent indexing requests, so it can recover from the last correct snapshot of the index.