1.环境：
SCOTT@test01p> @ ver1
PORT_STRING                    VERSION        BANNER                                                                               CON_ID
------------------------------ -------------- -------------------------------------------------------------------------------- ----------
IBMPC/WIN_NT64-9.1.0           12.2.0.1.0     Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production              0

2.测试例子：
$ cat get-curr-ospid.sql

-- get-curr-ospid.sql
--
-- get the server OS Pid for the current session
-- Jared Still jkstill@gmail.com still@pythian.com
col username format a20

select
    s.username,
    s.sid,
    p.spid
from v$session s, v$process p
where s.sid = sys_context('userenv','sid')
    and p.addr = s.paddr
order by username, sid
/

$ cat select.sql

@get-curr-ospid

prompt
prompt Testing speed of 'select into var'
prompt
prompt Press ENTER when ready
prompt

accept dummy
prompt Working...
prompt

set timing on

declare
    vDate date;
begin
    for i in 1..1e6
    loop
        select sysdate into vDate from dual;
    end loop;
end;
/

$ cat assign.sql

@get-curr-ospid

prompt
prompt Testing speed of 'var := something'
prompt
prompt Press ENTER when ready
prompt

accept dummy
prompt Working...
prompt