On 1/21/2016 11:57 PM, jimi.hulleg...@svensktnaringsliv.se wrote: > Long story short, we use a CMS that is integrated with Solr 4.6, with the > solrj jar file in the global/common Tomcat classpath. We currently use a > Google Search Appliance machine for our own freetext search needs, but plan > to replace that with some other solution in the near future. Since we already > work with solr because of the CMS integration, we would like to select solr > for this project. > > But I would prefer to use the latest version, ie solr 5, and I am not sure > how that would work in our situation. Can we use the solrj client for solr 4 > when indexing and searching on a solr 5 server? If so, would we miss some > important feature, and would this setup be future proof? > > Or can we somehow use both solr4 and solr 5 client libraries at the same > time, in the same context? It is not possible to upgrade the solr server that > the CMS is using, and it is not possible to remove the 4.6 solrj jar from the > common classpath in Tomcat. That is, unless the solr 5 version of solrj is > backwards compatible, so that we can switch the jar files and our CMS would > still be able to index and search in it's own solr 4 server.
If you are NOT running SolrCloud, then that should work with no problem. The HTTP API is fairly static and has not seen any major upheaval recently. If you're NOT running SolrCloud, you may even be able to replace the SolrJ jar in your existing system with the 5.4.1 version (and update SolrJ's dependent jars) and have everything continue to work. If you ARE running SolrCloud, I would not try mixing 4.x and 5.x, in either direction. SolrCloud is evolving very quickly ... I wouldn't even mix *minor* versions, much less *major* versions. There are differences in how the zookeeper database is laid out, and mixing versions is not guaranteed to work, especially if SolrJ is older than Solr. If the version difference is small and SolrJ is newer than Solr, there's a chance of success, but with the situation you have described, SolrCloud would likely not work. I have no idea about whether or not you can mix SolrJ versions in your client project. This is extremely tricky to get working right with Java in general, and may not be possible. Thanks, Shawn
