DISCARD

Discards the session state.

Synopsis

DISCARD { ALL | PLANS | SEQUENCES | TEMPORARY | TEMP }

Description

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.

Apache Cloudberry does not support invoking DISCARD ALL in a transaction.

Parameters

PLANS

Releases all cached query plans, forcing re-planning to occur the next time the associated prepared statement is used.

SEQUENCES

Discards all cached sequence-related state, including any preallocated sequence values that have not yet been returned by nextval(). (See CREATE SEQUENCE for a description of preallocated sequence values.)

TEMPORARY/TEMP

Drops all temporary tables created in the current session.

ALL

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:

    CLOSE ALL;
    SET SESSION AUTHORIZATION DEFAULT;
    RESET ALL;
    DEALLOCATE ALL;
    UNLISTEN *;
    SELECT pg_advisory_unlock_all();
    DISCARD PLANS;
    DISCARD SEQUENCES;
    DISCARD TEMP;

Notes

DISCARD ALL cannot be run inside a transaction block.

Compatibility

DISCARD is a Apache Cloudberry extension.