Deepak Mahto shares some advice:
The PL/pgSQL language, available as a default extension in PostgreSQL, provides powerful tools and flexibility for application developers to build complex, enterprise-scale functionality within the database. Through PL/pgSQL’s functions and procedures, developers can choose different volatility categories—
IMMUTABLE, STABLE, or VOLATILE—that offer varying performance benefits, especially in terms of result caching and data state awareness. For a deeper dive, refer to the official documentation. Choosing the appropriate volatility for a function is crucial; as they say, “With great power comes great responsibility.“
Read on to learn more. It seems like it would be quite easy to mess this up.