Also called show grants before and after set role. Unfortunately the role
privileges printing are not implemented yet.

The testcase checks to see if the privileges are set accordingly to a newly
created user. This is the most general usecase.

The testcase checks to see if the create user command sets the is_role column
to 'N' by default

SET ROLE NONE;

separate function.

as well as only set privileges in the update() function.

the current user via the current security_context

roles

Renaming a user via RENAME USER command causes either the user columns
to update, or the role columns.

The function now handles user updates/deletions correctly.

Also fixed a bug regarding the HASH iteration. It previously got
the stop condition from a different hashtable and this caused errors
when the hash sizes were different.

consistent.

The logic is not complete yet.

no longer valid entries in the roles_mappings HASH. This job will be delegated
to handle_grant_* functions

It will only hold _valid_ entries for as long as it held in memory. Any change
regarding acl_users or acl_roles in memory should update the structure
immediately. This is why the rebuild_roles_mappings no longer removes invalid
entries.

In order to keep things consistent with the existing code, the following jobs
are assigned to each function:

The role of rebuild_roles_mappings is to recreate the links between users and
roles. Any other updates are to be done in the functions:

handle_grant_*

This change prepares the code for the next step, which is cascading updates.

function

Also removed code that loads that column into memory.

No cascading changes take place during a user rename. This needs to be
addressed.

user creation.

No more memory leaks in the code.

Still problems with hashtable acl_roles
Need to create a copy of grant_roles, currently it uses the same buffer