That is strange indeed. The usual culprit is that there is a commit in there and no autowarming, so you see pauses when the first query hits after a commit. But you say you only build the index once which would seem to rule that out.
I'd be interested in what is in your Solr logs around the time in question. Say 10,000 lines leading up to a slow query (10,000 lines is completely arbitrary, hopefully it's enough to see something interesting). Best, Erick On Tue, Jun 24, 2014 at 5:26 AM, RadhaJayalakshmi <rlakshminaraya...@inautix.co.in> wrote: > I am running Solr 4.5.1. Here is how my setup looks: > > Have 2 modest sized Collections. > Collection 1 - 2 shards, 3 replicas (Size of Shard 1 - 115 > MB, Size of Shard 2 - 55 MB) > Collection 2 - 2 shards, 3 replicas (Size of Shard 2 - 3.5 > GB, Size of Shard 2 - 1 GB) > These two collections are distributed across: > 6 Tomcat Nodes setup on 3 VMs (2 Nodes per VM) > Each of the 6 Tomcat nodes has a XmS / XmX setting of 2 GB > Each of the 3 VMs have a Physical Memory (RAM) of 32 GB > > As you can see my Collections are pretty small - This is actually a test > environment (and NOT Production), However my users (only have a handful of > testers) are complaining of sporadic performances issues on the Search. > > Here are my observations from the application logs: > 1) Out of 200 sample searches across both collections - 13 requests are slow > (3 slow responses on Collection 1 and 10 slow responses on Collection 2). > > 2) When things run fast - they are really fast (Qtimes of 25 - 100 > milliseconds) - but when things are slow - I can see that the QTime > consistently hovers around the 5 second (or 5000 millisecond mark). I am > seeing responses of the order of 5024, 5094, 5035 ms - as though something > just hung for 5 seconds. I am observing this 5 second delay on both > Collections - which I feel is unusual - because both contain very different > data sets. I am unable to figure out whats causing the QTime to be so > consistent around the 5 second mark. > > 3) I build my index only once. I did try running an optimize on both > Collection 1 and Collection 2 after the users complained - I did notice that > post the optimize the segment count on each of the four shards did come down > - but that still didn't resolve the slowness on the searches (I was hoping > it would). > > 4) I am looking at the Solr Dashboard for more clues - My TomCat nodes are > definitely NOT running out of memory - the 6 nodes are consuming anywhere > between 500 MB - 1 GB RAM > > 5) The File Descriptor counts are under control - can only see a maximum of > 100 file descriptors being used of a total of 4096 > > 6) The Solr dashboard is however showing that 0.2% (or 9.8MB) of Swap Space > being consumed on one of the 3 VMs. Is this a concern ? > > 7) Also looked at the Plugin / Stats for every core on the Solr Dashboard. I > can't see any evictions happening in any of the caches - Its always ZERO. > > Has anyone encountered such an issue ? What else should I be looking for to > debug my problem ? > > Thanks > > > > -- > View this message in context: > http://lucene.472066.n3.nabble.com/Slow-QTimes-5-seconds-for-Small-sized-Collections-tp4143681.html > Sent from the Solr - User mailing list archive at Nabble.com.
