The doc is silent on this issue of SolrJ vs. server version compatibility in general (e.g., 4 vs. 5.) That's not an absolute assurance, but at least it's a possibility. And and far as I know, if you had a SolrJ 4 app and upgraded the server (with no change in the index or data model), the app should work fine. So... if you stick with SolrJ 4 and use the Solr 4 doc as your guide, you should be okay. That's the theory.
Worst case, you would have to deploy a Solr 4 server. That's not the preferred choice, but is a decent backup plan. -- Jack Krupansky On Fri, Jan 22, 2016 at 10:19 AM, Shawn Heisey <apa...@elyograg.org> wrote: > 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 > >
