psql: cannot run DISCARD ALL with AUTOCOMMIT = 'off'

seb=> select version();
                                               version
------------------------------------------------------------------------------------------------------
 PostgreSQL 8.4.4 on x86_64-pc-linux-gnu, compiled by GCC gcc-4.4.real (Debian 4.4.4-7) 4.4.4, 64-bit
(1 row)

Time: 0,074 ms
seb=> abort;
ROLLBACK
Time: 0,086 ms
seb=> DISCARD ALL ;
ERROR:  DISCARD ALL cannot run inside a transaction block

DISCARD is not mentioned anywhere in the src/bin/psql/common.c
in command_no_begin(const char *query) function.
I don't know, may be this is expected behavior.

--
Sergey Burladyan