restores run-time parameters to their default values.
is an alternative spelling for
SET configuration_parameter TO DEFAULT
The default value is defined as the value that the parameter would have had, if no
had ever been issued for it in the current session. The actual source of this value might be a compiled-in default, the configuration file, command-line options, or per-database or per-user default settings. This is subtly different from defining it as
the value that the parameter had at session start, because if the value came from the configuration file, it will be reset to whatever is specified by the configuration file now. See
Chapter 18, Server Configuration, in the documentation
The transactional behavior of
is the same as
SET: its effects will be undone by transaction rollback.