TRUNCATE
Deletes all of the rows from a table without doing a table scan: this operation is a faster alternative to an unqualified DELETE operation. To run a TRUNCATE command, you must be have the TRUNCATE TABLE permission, be the owner of the table, or a superuser. To grant permissions to truncate a table, use the GRANT command.
TRUNCATE is much more efficient than DELETE and doesn't require a VACUUM and ANALYZE. However, be aware that TRUNCATE commits the transaction in which it is run.
Syntax
TRUNCATE [ TABLE ] table_name
The command also works on a materialized view.
TRUNCATE materialized_view_name
Parameters
- TABLE
-
Optional keyword.
- table_name
-
A temporary or persistent table. Only the owner of the table or a superuser may truncate it.
You can truncate any table, including tables that are referenced in foreign-key constraints.
You don't need to vacuum a table after truncating it.
- materialized_view_name
-
A materialized view.
You can truncate a materialized view that is used for Streaming ingestion.
Usage notes
The TRUNCATE command commits the transaction in which it is run; therefore, you can't roll back a TRUNCATE operation, and a TRUNCATE command may commit other operations when it commits itself.
Examples
Use the TRUNCATE command to delete all of the rows from the CATEGORY table:
truncate category;
Attempt to roll back a TRUNCATE operation:
begin; truncate date; rollback; select count(*) from date; count ------- 0 (1 row)
The DATE table remains empty after the ROLLBACK command because the TRUNCATE command committed automatically.
The following example uses the TRUNCATE command to delete all of the rows from a materialized view.
truncate my_materialized_view;
It deletes all records in the materialized view and leaves the materialized view and its schema intact. In the query, the materialized view name is a sample.