Unanswered: SPs can not modify system tables even for sa
It seems that SQL Server is behaving in really strange way, when executing sp_changedbowner SP in a database to assign a database owner to a database, SQL Server respond that it can do it because it has not SSO role.
The query select show_role() shows sa_role and sso_role among others.
If "allow updates" is set, then I can do the same updates in as in the stored procedure manually, but still it the SP does not work.
Further checks show that problem appears for every SP that needs to modify system tables, like sp_modifylogin, even for simple things like "max failed_logins".
Checked master, sybsystemprocs, compared with another ASE and nothing found.
I would really appreciate any hint.
Just read the correct document. This is included in the SAG (ASE 12.5.1):
1 Use sp_configure to set allow updates to system tables to on.
2 Create the stored procedure with the create procedure command.
3 Use sp_configure to set allow updates to system tables to off.
Now, the point is why installmaster did not set this option to "on" before creating the SPs, but that is another issue.