DESCRIPTION: Add support for ALTER DATABASE OWNER
This adds support for changing the database owner. It achieves this by marking the database as a distributed object. By marking the database as a distributed object it will look for its dependencies and order the user creation commands (enterprise only) before the alter of the database owner. This is mostly important when adding new nodes.
By having the database marked as a distributed object it can easily understand for which `ALTER DATABASE ... OWNER TO ...` commands to propagate by resolving the object address of the database and verifying it is a distributed object, and hence should propagate changes of owner ship to all workers.
Given the ownership of the database might have implications on subsequent commands in transactions we force sequential mode for transactions that have a `ALTER DATABASE ... OWNER TO ...` command in them. This will fail the transaction with meaningful help when the transaction already executed parallel statements.
By default the feature is turned off since roles are not automatically propagated, having it turned on would cause hard to understand errors for the user. It can be turned on by the user via setting the `citus.enable_alter_database_owner`.
DESCRIPTION: Alter role only works for citus managed roles
Alter role was implemented before we implemented good role management that hooks into the object propagation framework. This is a refactor of all alter role commands that have been implemented to
- be on by default
- only work for supported roles
- make the citus extension owner a supported role
Instead of distributing the alter role commands for roles at the beginning of the node activation role it now _only_ executes the alter role commands for all users in all databases and in the current database.
In preparation of full role support small refactors have been done in the deparser.
Earlier tests targeting other roles than the citus extension owner have been either slightly changed or removed to be put back where we have full role support.
Fixes#2549
* Improve extension command propagation tests
* patch for hardcoded citus extension name
(cherry picked from commit 0bb3dbac0afabda10e8928f9c17eda048dc4361a)
Nils Dijk
Halil Ozan Akgul
Jelte Fennema
Onur TIRTIR