Enum pgx::guc::GucContext

pub enum GucContext {
    Internal,
    Postmaster,
    Sighup,
    SuBackend,
    Backend,
    Suset,
    Userset,
}

Variants

Internal

cannot be set by the user at all, but only through internal processes ("server_version" is an example). These are GUC variables only so they can be shown by SHOW, etc.

Postmaster

can only be set when the postmaster starts, either from the configuration file or the command line.

Sighup

can only be set at postmaster startup or by changing the configuration file and sending the HUP signal to the postmaster or a backend process. (Notice that the signal receipt will not be evaluated immediately. The postmaster and the backend check it at a certain point in their main loop. It's safer to wait than to read a file asynchronously.)

SuBackend

can only be set at postmaster startup, from the configuration file, or by client request in the connection startup packet (e.g., from libpq's PGOPTIONS variable).

Backend

can be set from the startup packet only when the user is a superuser. Furthermore, an already-started backend will ignore changes to such an option in the configuration file. The idea is that these options are fixed for a given backend once it's started, but they can vary across backends.

Suset

can be set at postmaster startup, with the SIGHUP mechanism, or from the startup packet or SQL if you're a superuser.

Userset

can be set by anyone any time.