On 5/2/2017 10:53 AM, Shashank Pedamallu wrote: > I want to unload a core from Solr without deleting data-dir or instance-dir. > I’m performing some operations on the data-dir after this and then I would > like to reload the core from the same data-dir. These are the things I tried: > > 1. Reload api – throws an exception saying no such core exists. > 2. Create api – throws an exception saying a core with given name already > exists. > > Can someone point me what api I could use to achieve this. Please note that, > I’m working with Solr in Non-Cloud mode without Zookeeper, Collections, etc.
The RELOAD command isn't going to work at all because the core has been unloaded -- Solr doesn't know about the core, so it can't reload it. This is a case where the language used is somewhat confusing, even though it's completely correct. I am about 90 percent certain that the reason the CREATE command gave you an error message is because you tried to make a new core.properties file before you did the CREATE. When things are working correctly, the CREATE command itself is what will create core.properties. If it already exists, CoreAdmin will give you an error. This is the exact text of the error I encountered when trying to use CREATE after building a core.properties file manually: Error CREATEing SolrCore 'foo': Could not create a new core in C:\Users\sheisey\Downloads\solr-6.5.1\server\solr\fooas another core is already defined there That error message is confusing, so I will be fixing it: https://issues.apache.org/jira/browse/SOLR-10599 To verify what you need to do, I fired up Solr 6.5.1 from an extracted download directory. I created two cores, "foo" and "bar", using the commandline "bin\solr create" command. Then I went to the admin UI and unloaded foo. The foo directory was still there, but the core was gone from Solr's list. By clicking on the "Add Core" button in the Core Admin tab, typing "foo" into name and instanceDir, and clearing the other text boxes, the core was recreated exactly as it was before it was unloaded. This is the log from the CREATE command that the admin UI sent: 2017-05-02 18:02:49.232 INFO (qtp1543727556-18) [ x:foo] o.a.s.s.HttpSolrCall [admin] webapp=null path=/admin/cores params={schema=&dataDir=&name=foo&action=CREATE&config=&instanceDir=foo&wt=json&_=1493747904891} status=0 QTime=396 To double-check this and show how it can be done without the admin UI, I accessed these two URLs (in a browser), and accomplished the exact same thing again. The first URL unloads the core, the second asks Solr to find the core and re-add it with default settings. http://localhost:8983/solr/admin/cores?action=UNLOAD&core=foo http://localhost:8983/solr/admin/cores?action=CREATE&name=foo&instanceDir=foo If you are using additional options with your cores, such as the configset parameter, you would need to include those options on your CREATE call, similar to what you might have done when you initially created the core. With some of the options you can use, re-adding a core might be better done by re-creating the correct core.properties file and restarting Solr so it discovers the core. Erick, I seem to remember the "core.properties.unloaded" rename happening in the past as well, but when I unloaded on 6.5.1, the core.properties file was simply deleted. I don't think that's a good idea because it may contain information that's not available anywhere else. Thanks, Shawn
