# TRUNCATE(7) - man - phpMan

[TRUNCATE(7)](https://www.chedong.com/phpMan.php/man/TRUNCATE/7/markdown)                        PostgreSQL 14.23 Documentation                        [TRUNCATE(7)](https://www.chedong.com/phpMan.php/man/TRUNCATE/7/markdown)



## NAME
       TRUNCATE - empty a table or set of tables

## SYNOPSIS
       TRUNCATE [ TABLE ] [ ONLY ] _name_ [ * ] [, ... ]
           [ RESTART IDENTITY | CONTINUE IDENTITY ] [ CASCADE | RESTRICT ]

## DESCRIPTION
       **TRUNCATE** quickly removes all rows from a set of tables. It has the same effect as an
       unqualified **DELETE** on each table, but since it does not actually scan the tables it is
       faster. Furthermore, it reclaims disk space immediately, rather than requiring a subsequent
       **VACUUM** operation. This is most useful on large tables.

## PARAMETERS
       _name_
           The name (optionally schema-qualified) of a table to truncate. If ONLY is specified
           before the table name, only that table is truncated. If ONLY is not specified, the table
           and all its descendant tables (if any) are truncated. Optionally, * can be specified
           after the table name to explicitly indicate that descendant tables are included.

       RESTART IDENTITY
           Automatically restart sequences owned by columns of the truncated table(s).

       CONTINUE IDENTITY
           Do not change the values of sequences. This is the default.

       CASCADE
           Automatically truncate all tables that have foreign-key references to any of the named
           tables, or to any tables added to the group due to CASCADE.

       RESTRICT
           Refuse to truncate if any of the tables have foreign-key references from tables that are
           not listed in the command. This is the default.

## NOTES
       You must have the TRUNCATE privilege on a table to truncate it.

       **TRUNCATE** acquires an ACCESS EXCLUSIVE lock on each table it operates on, which blocks all
       other concurrent operations on the table. When RESTART IDENTITY is specified, any sequences
       that are to be restarted are likewise locked exclusively. If concurrent access to a table is
       required, then the **DELETE** command should be used instead.

       **TRUNCATE** cannot be used on a table that has foreign-key references from other tables, unless
       all such tables are also truncated in the same command. Checking validity in such cases would
       require table scans, and the whole point is not to do one. The CASCADE option can be used to
       automatically include all dependent tables — but be very careful when using this option, or
       else you might lose data you did not intend to! Note in particular that when the table to be
       truncated is a partition, siblings partitions are left untouched, but cascading occurs to all
       referencing tables and all their partitions with no distinction.

       **TRUNCATE** will not fire any ON DELETE triggers that might exist for the tables. But it will
       fire ON TRUNCATE triggers. If ON TRUNCATE triggers are defined for any of the tables, then
       all BEFORE TRUNCATE triggers are fired before any truncation happens, and all AFTER TRUNCATE
       triggers are fired after the last truncation is performed and any sequences are reset. The
       triggers will fire in the order that the tables are to be processed (first those listed in
       the command, and then any that were added due to cascading).

       **TRUNCATE** is not MVCC-safe. After truncation, the table will appear empty to concurrent
       transactions, if they are using a snapshot taken before the truncation occurred. See
       Section 13.5 for more details.

       **TRUNCATE** is transaction-safe with respect to the data in the tables: the truncation will be
       safely rolled back if the surrounding transaction does not commit.

       When RESTART IDENTITY is specified, the implied **ALTER** **SEQUENCE** **RESTART** operations are also
       done transactionally; that is, they will be rolled back if the surrounding transaction does
       not commit. Be aware that if any additional sequence operations are done on the restarted
       sequences before the transaction rolls back, the effects of these operations on the sequences
       will be rolled back, but not their effects on **currval()**; that is, after the transaction
       **currval()** will continue to reflect the last sequence value obtained inside the failed
       transaction, even though the sequence itself may no longer be consistent with that. This is
       similar to the usual behavior of **currval()** after a failed transaction.

       **TRUNCATE** can be used for foreign tables if supported by the foreign data wrapper, for
       instance, see postgres_fdw.

## EXAMPLES
       Truncate the tables bigtable and fattable:

           TRUNCATE bigtable, fattable;

       The same, and also reset any associated sequence generators:

           TRUNCATE bigtable, fattable RESTART IDENTITY;

       Truncate the table othertable, and cascade to any tables that reference othertable via
       foreign-key constraints:

           TRUNCATE othertable CASCADE;

## COMPATIBILITY
       The SQL:2008 standard includes a **TRUNCATE** command with the syntax TRUNCATE TABLE _tablename_.
       The clauses CONTINUE IDENTITY/RESTART IDENTITY also appear in that standard, but have
       slightly different though related meanings. Some of the concurrency behavior of this command
       is left implementation-defined by the standard, so the above notes should be considered and
       compared with other implementations if necessary.

## SEE ALSO
       [**DELETE**(7)](https://www.chedong.com/phpMan.php/man/DELETE/7/markdown)



PostgreSQL 14.23                                2026                                     [TRUNCATE(7)](https://www.chedong.com/phpMan.php/man/TRUNCATE/7/markdown)