Hello, Most likely due to the operating system caching the relevant portions of the index after the first set of queries.
Otis -- Sematext is hiring -- http://sematext.com/about/jobs.html?mls Lucene, Solr, Nutch, Katta, Hadoop, HBase, UIMA, NLP, NER, IR ----- Original Message ---- > From: Dinh <pcd...@gmail.com> > To: java-user@lucene.apache.org > Sent: Tue, November 17, 2009 12:39:14 PM > Subject: Why Lucene takes longer time for the first query and less for > subsequent ones > > Hi all, > > I made a list of 4 simple, singe term queries and do 4 searches via Lucene > and find that if the term is used for search in the first time, Lucene takes > quite a bit time to handle it. > > - Query A > 00:27:28,781 INFO LuceneSearchService:151 - Internal search took > 328.21463ms > 00:27:28,781 INFO SearchController:86 - Page rendered in 338.29553ms > > - Query B > 00:27:39,171 INFO LuceneSearchService:151 - Internal search took > 480.30908ms > 00:27:39,187 INFO SearchController:86 - Page rendered in 493.07327ms > > - Query C > 00:27:46,765 INFO LuceneSearchService:151 - Internal search took > 189.33635ms > 00:27:46,765 INFO SearchController:86 - Page rendered in 195.43823ms > > - Query D > 00:28:00,312 INFO LuceneSearchService:151 - Internal search took 330.3596ms > 00:28:00,328 INFO SearchController:86 - Page rendered in 347.34747ms > > > It looks no good at the first glance because I have only 500 000 indexed > documents. However, when I searched them again I found that Lucene run much > faster. > > - Query A > 00:28:04,046 INFO LuceneSearchService:151 - Internal search took 3.90301ms > 00:28:04,062 INFO SearchController:86 - Page rendered in 15.694173ms > > - Query C > 00:28:15,390 INFO LuceneSearchService:151 - Internal search took 1.425879ms > 00:28:15,390 INFO SearchController:86 - Page rendered in 7.946541ms > > - Query D > 00:28:26,031 INFO LuceneSearchService:151 - Internal search took 1.849956ms > 00:28:26,046 INFO SearchController:86 - Page rendered in 12.023037ms > > - Query B > 00:28:31,609 INFO LuceneSearchService:151 - Internal search took 1.668648ms > 00:28:31,625 INFO SearchController:86 - Page rendered in 15.57237ms > > Why does it happens? Does it mean that Lucene has an internal cache engine, > just like MySQL query result cache or Oracle query execution plan cache? > > Thanks > > Dinh --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
