2 large databases - worth merging into 1?

I have 2 large databases that were shared before. I now have removed the sharing and have created a new database with all of the data except for the tables that were开发者_JAVA百科 originally shared. Is it worth importing this data into the new database, or keeping them as separate entities that I can just scan through? We are talking around 60million records in each shared table, of which there are 2 tables.

Also, whilst I have an empty table, should I be adding indexes which weren't thought of when the database was originally constructed and now too large to add them?

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I have decided to merge the databases. I took a good look at what indexes were missing and adding them whilst the table was empty. These indexes have improved the speed and efficiency of the large tables.