On 7/17/2014 11:15 PM, search engn dev wrote: > I just want to understand query flow and how load balancing works in case of > LBHttpSolrServer. We have setup SolrCloud with one collection, and that > collection has 4 shards and each shard has two nodes i.e one master and one > replica.
If you're running SolrCloud and building client applications with SolrJ, just use CloudSolrServer. You just pass it the same zkHost value that you give to SolrCloud itself, listing all your zookeeper servers. The CloudSolrServer object is a zookeeper client, so my understanding is that it will dynamically adjust to the current clusterstate -- if servers go down, get added, or get removed, the client will know as soon as SolrCloud itself does, without restarting the application or building a new client object. CloudSolrServer will automatically load balance requests across the nodes that comprise the collection that is being queried. Newer versions of the client will also route updates directly to the leader of the correct shard, which reduces load on the servers and speeds up indexing. Internally, CloudSolrServer uses an instance of LBHttpSolrServer, but the list of URLs is dynamically managed, your program doesn't need to worry about it. http://lucene.apache.org/solr/4_9_0/solr-solrj/org/apache/solr/client/solrj/impl/CloudSolrServer.html Side questions/comments for experienced committers, I can file some issues and work on these: The javadoc for the first CloudSolrServer constructor just mentions HOST:PORT for the format of zkHost. Should that be expanded so that it's apparent that if multiple ZK servers are present, they all need to be listed? All of the constructor javadocs could do with a little more substance. I think that "throws MalformedURLException" needs to be removed from the second CloudSolrServer constructor. When I tried that, eclipse didn't show any errors. Although it's not complex code, the various CloudSolrServer constructors are very similar, the actual work should probably be done by one constructor that is called by all the others. Thanks, Shawn
