=====PostgreSQL provides a set of default roles which provide access to certain, commonly needed, privileged capabilities and information. Administrators can GRANT these roles to users and/or other roles in their environment, providing those users with access to the specified capabilities and information.
The default roles are described in 表 21-1. Note that the specific permissions for each of the default roles may change in the future as additional capabilities are added. Administrators should monitor the release notes for changes.
表 21-1. Default Roles
|pg_signal_backend||Send signals to other backends (eg: cancel query, terminate).|
Administrators can grant access to these roles to users using the GRANT command:
GRANT pg_signal_backend TO admin_user;