Moving Catalog: Use matching tables, Create new tables

Moving Catalog: Use matching tables, Create new tables

  
When you move a eSpace from one database to another database, Outsystems prompts you to select either "Use matching tables" or "Create new tables", as you can see here https://goo.gl/kUPjQL

If you select "Use matching tables" technically what does this actually do under the hood?
1)outsystems will try to find physical matching tables that match outsystems entity tables previously configured
(and if it found some matching table but not all? or it doesnt find any matching tables at all? what happens?)
OR
2) outsystems copy the table over from one database to the new database on its own.