Sitecore SOLR core pointing to different core directory

Question

I have setup the SOLR with switch on rebuild configuration. But after setting it up I am facing a weird issue like my SOLR web index core is pointing to different SOLR index directory.

Let me explain, When I check the sitecore_web_index from the SOLR panel then I can see in the Instance section that my Sitecore secondary web index (sitecore_web_index_sec) is pointing to the main Sitecore web index (sitecore_web_index) and main Sitecore web index is pointing to the Sitecore secondary web index.

For example, you can see in the screenshot below that when I check secondary web index (red box) then it is pointing to the Sitecore main index directory data (green box).

This is vice versa (see screenshot below)

I checked the core.properties file for both web index directory. For the main Sitecore index it is as below:

#Written by CorePropertiesLocator
#Mon Apr 26 08:48:41 UTC 2021
config=solrconfig.xml
name=sitecore_web_index
schema=schema.xml
dataDir=data

and, for the Sitecore secondary web index it is as:

#Written by CorePropertiesLocator
#Mon Apr 26 08:48:41 UTC 2021
config=solrconfig.xml
name=sitecore_web_index_sec
schema=schema.xml
dataDir=data

Do you have any idea why is it happening?

Answer 1

This is how SwitchOnRebuildSolrSearchIndex solr works , this is not a bug.

Your website uses indexes from the primary core. Each time you initiate a full index rebuild, Sitecore does this in the secondary core. The secondary core then becomes the primary one after the rebuild.

You can read more about it in @Marek blog - https://www.skillcore.net/sitecore/using-switchonrebuildsolrsearchindex-solr-provider-for-sitecore and Sitecore article - https://doc.sitecore.com/developers/90/platform-administration-and-architecture/en/switch-solr-indexes.html

So that means your website will always use the primary core for results, it will switch these after the index is completed.