I'm building a Next.js application and want to add authentication. Has anyone implemented NextAuth.js with custom credentials provider? Any example code or best practices would be greatly appreciated.

Our application is facing performance issues with PostgreSQL as our dataset grows. We're currently using standard SELECT queries with multiple JOINs that worked fine with smaller datasets. What strategies should we implement for optimizing these queries?

I'm trying to understand when to use Server Components vs. Client Components in React. What are the best use cases for each, and how do they communicate with each other?