title: CPU usage when searching using solr
body: <p>We have a solr cloud setup of 4 shards (one shard per physical machine) having ~100 million documents. Zookeeper is on one of those 4 machines. We encounter complex queries having wild cards and proximity searches together and it sometimes takes more than 15 secs to get top 100 documents. Query traffic is very very low at the moment (2-3 queries every minute). 4 Servers hosting cloud have following specs:
  (2 servers -> 64 GB RAM, 24 CPU cores, 2.4 GHz) + (2 servers -> 48 GB RAM, 24 CPU cores, 2.4GHz).</p>
  
  <p>We are providing 8 GB JVM memory per shard. Our 510GB index on SSDs per machine (totalling to 4*510 GB = 2.4TB) is mapped into OS disk cache on remaining RAM on each server. So I suppose RAM is not an issue for us.</p>
  
  <p>Now Interesting thing to note is: When a query is fired to the cloud, only one CPU core is utilized to 100% and rest are all at 0%. Same behaviour is replicated on all the machines. No other processes are running on these machines. </p>
  
  <p>Shouldn't solr be doing multi-threading of some-kind to utilize the CPU cores? Can I anyhow increase CPU consumption for each queries as traffic is not a problem. If so, how?</p>