Previous sections gave a brief introduction to RLS, including some common use cases. They also showed how to implement RLS using a few different methods. This section focuses on performance and potential issues you may encounter.
There are two main areas where RLS can impact performance. The first is the user or authentication lookup. Some kind of lookup must be performed in the access predicate to determine either the user name, group membership, or specific values in the session context. Considering that RLS is non-prescriptive, the lookup isn’t confined to these methods, but they are very easy methods to use