They are logically different that is why kept in different collections. Collection1: The purpose is to do Global Text Search for all objects through multiple document types Collection3: The purpose is to have search for some other type of objects whose documents are in Millions and takes GBs size.
On very specific purpose we need to go to collection3 and do JOIN with collection1 to fetch some data and facets Then go to collection1 and JOIN with collection3 to get facets of collection1 but no data. -- Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html