The fasttrun module provides transaction unsafe function to truncate temporary tables without growing pg_class size.

This module is required for 1C Enterprise support.

Fast truncate operation is not transactional, so its results cannot be rolled back and become immediately visible in all sessions regardless of isolation level.

 select fasttruncate('TABLE_NAME'); 

 create or replace function f() returns void as $$ begin for i in 1..1000 loop PERFORM fasttruncate('tt1'); end loop; end; $$ language plpgsql;