On 3/14/2018 12:56 AM, Akshay Murarka wrote:
I am using solr-5.4.0 in my production environment and am trying to automate the reload/restart process of the solr collections based on certain specific conditions.I noticed that on solr reload the thread count increases a lot there by resulting in increased latencies. So I read about reload process and came to know that while reloading 1) Solr creates a new core internally and then assigns this core same name as the old core. Is this correct? 2) If above is true then does solr actually create a new index internally on reload? 3) If so then restart sounds much better than reload, or is there any better way to upload new configs on solr? 4) Can you point me to any docs that can give me more details about this?
When you reload a core, Solr creates a new SolrCore object. Any changes to the configuration are activated at that time. This is pretty much exactly the same as what happens when Solr initially starts up, or when you create a brand new core.
After the SolrCore object is created, part of the process of starting the core is looking for an existing index and opening it. Solr doesn't build the entire index on reload -- that's not something Solr can do. If it WERE something Solr could do, the amount of time required would be enormous in most cases. For the big indexes in my Solr install, this might be as long as twelve hours.
Once the new SolrCore is fully operational after the reload, it replaces the old SolrCore object and takes over all of its responsibilities. The old object becomes garbage for Java to collect.
Thanks, Shawn
