answer:Establishing a database connection is one of the most expensive database operations. It requires authentication, opening files on a disk, creating memory caches, etc. This might make you think that opening two persistent connections is the way to go, but it really depends on how your site is used. If the vast majority of your users are only performing SELECT operations, then opening that second persistent connection to the master database will eat up memory and slow the loading of the ever-important landing page. As with many design problems, the correct solution requires understanding how your users will be using your application. Once you understand that, you can do some benchmarking and make the correct decisions about how to optimize your application. Is it possible for you to intelligently connect users to the correct database (e.g., connect a user to the master database only after they have logged in as an "editor" or some similar role)?