I know there are several questions similar to this but they don\'t provide a simple answer to the problem at hand. Sorry if you feel this is a duplicate but I think clear and un
You may want to take a look at Apache Solr 3.3 with RankingAlgorithm 1.2. It supports NRT (Near Real Time Indexing) and can update 10,000 docs / sec. You can concurrently search during the updates. You do not need to commit or close the searchers. You can get more information about NRT with Solr 3.3 with RankingAlgorithm from here:
http://solr-ra.tgels.org/wiki/en/Near_Real_Time_Search_ver_3.x