Hi Lucene experts, I'm having a problem with Sort performance during searches. I'm using Lucene 1.9.1.
I need to Sort by a date field in the document. When I use the default Sort.RELEVANCE, query response time is ~6ms. However, when I specify a sort, e.g. Searcher.search( query, new Sort( "mydatefield" ) ), the query response time gets multiplied by a factor of 10 or 20. Also, CPU usage shoots up to nearly 90%. Is this expected behavior? I thought the default sort and sort by field should perform roughly the same when the values are cached in memory, since they both have to do a top-K ranking over the same number of raw hits. The performance gets disproportionately worse as I increase the number of parallel threads that query the same Searcher object. Also, in my previous experience with sorting by a field in Lucene, I seem to remember there being a preload time when you first search with a sort by field, sometimes taking 30 seconds or so to load all of the field's values into the in-memory cache associated with the Searcher object. This initial preload time doesn't seem to be happening in my case -- does that mean that for some reason Lucene is not caching the field values? I have an index of 1 million documents, taking up about 1.7G of diskspace. I specify -Xmx2000m when running my java search application. Any advice or insight would be much appreciated. Thanks, ~Heng --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
