DISCARD releases internal resources associated with a database session. This command is useful for partially or fully resetting the session's state. There are several subcommands to release different types of resources; the DISCARD ALL variant subsumes all the others, and also resets additional state.
Releases all cached query plans, forcing re-planning to occur the next time the associated prepared statement is used.
Discards all cached sequence-related state,
including currval()/lastval()
information and any preallocated sequence values that have not
yet been returned by nextval().
(See CREATE SEQUENCE for a description of
preallocated sequence values.)
Drops all temporary tables created in the current session.
Releases all temporary resources associated with the current session and resets the session to its initial state. Currently, this has the same effect as executing the following sequence of statements:
SET SESSION AUTHORIZATION DEFAULT; RESET ALL; DEALLOCATE ALL; CLOSE ALL; UNLISTEN *; SELECT pg_advisory_unlock_all(); DISCARD PLANS; DISCARD SEQUENCES; DISCARD TEMP;