I'm not the expert here, but perhaps what you're noticing is actually the OS's disk cache. The actual solr index isn't cached by solr, but as you read the blocks off disk the OS disk cache probably did cache those blocks for you. On the 2nd run the index blocks were read out of memory.
There was a very extensive discussion on this list not long back titled: "Re: SolrCloud loadbalancing, replication, and failover" look that thread up and you'll get a lot of in-depth on the topic. David -----Original Message----- From: Giammarco Schisani [mailto:giamma...@schisani.com] Sent: Thursday, May 09, 2013 2:59 PM To: solr-user@lucene.apache.org Subject: More Like This and Caching Hi all, Could anybody explain which Solr cache (e.g. queryResultCache, documentCache, fieldCache, etc.) can be used by the More Like This handler? One of my colleagues had previously suggested that the More Like This handler does not take advantage of any of the Solr caches. However, if I issue two identical MLT requests to the same Solr instance, the second request will execute much faster than the first request (for example, the first request will execute in 200ms and the second request will execute in 20ms). This makes me believe that at least one of the Solr caches is being used by the More Like This handler. I think the "documentCache" is the cache that is most likely being used, but would you be able to confirm? As information, I am currently using Solr version 3.6.1. Kind regards, Giammarco Schisani
