简体中文

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.

Database does not support invoking DISCARD ALL in a transaction.

arameters

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 Database extension.