> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/15/reference/sql-commands/discard.md).

# DISCARD

## DISCARD

DISCARD — discard 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.

### 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 `currval()`/`lastval()` information and any preallocated sequence values that have not yet been returned by `nextval()`. (See [CREATE SEQUENCE](/15/reference/sql-commands/create-sequence.md) for a description of preallocated sequence values.)

`TEMPORARY` or `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 TEMP;
DISCARD SEQUENCES;
```

### Notes

`DISCARD ALL` cannot be executed inside a transaction block.

### Compatibility

`DISCARD` is a PostgreSQL extension.

***

原文：[PostgreSQL 15.19 Documentation](/15/reference/sql-commands/discard.md)（英文原文，待翻譯）


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