Hi Herman, This is very likely due to JVM Garbage Collection, which can stop the whole app if not tuned correctly. We just did this tuning it for a client whose JVM would lock up like that for minutes at the time.
If you don't have Solr & JVM monitoring, you should consider getting - see http://sematext.com/spm/solr-performance-monitoring/index.html for a service that can monitor your Solr, JVM, OS, etc. If it is indeed GC that's causing this, you'll want to adjust sizes of different memory regions in the JVM (eden, survivor spaces, old gen), possibly pick a better garbage collector, etc. There is no exact recipe because each app is different. Otis ---- Sematext :: http://sematext.com/ :: Solr - Lucene - Nutch Lucene ecosystem search :: http://search-lucene.com/ ----- Original Message ----- > From: Herman Kiefus <herm...@angieslist.com> > To: "solr-user@lucene.apache.org" <solr-user@lucene.apache.org> > Cc: > Sent: Wednesday, October 12, 2011 10:12 AM > Subject: Extreme QTime > > We service about 25K of each particular query type per hour per server. > QTime > *averages* less than a second; however, there always a few (1-10) whose > QTimes > go way above (10 - 500 seconds) the average. If I harvest these queries from > the log an re-execute them they of course execute sub-second. Why are some > of > these queries running long? > > My first thought was perhaps these queries were occurring subsequent to > replication commits, which happen every 10 minutes; however, there seem to be > no > clustering of these events around a 10 minute periodic cycle. (Given that I > have not established any appropriate warming queries, this seemed a logical > conclusion). > > My next though was to compare the times that these queries executed versus > what > I see in the log file (grep SEVERE...) But I found nothing to correlate. > > Do you folks have any ideas? >
