Re: Why do i need to install set_user extension if i can directly grant all required privileges to user?

Changing roles is already possible in Postgres.  You must be a member of the
target role or be a superuser in order to change roles. 

This is going to change in detail as of version 16 of PostgreSQL. You may determine whether a role switch is allowed or not.

Excerpt from https://www.postgresql.org/docs/16/sql-grant.html:

"The SET option, if it is set to TRUE, allows the member to change to the granted role using the SET ROLE command. If a role is an indirect member of another role, it can use SET ROLE to change to that role only if there is a chain of grants each of which has SET TRUE. This option defaults to TRUE."

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