Query session parameter values of running session

I know this question is more than a year old, but in case anyone stumbles here like I did, you can query V$SES_OPTIMIZER_ENV:

SYS> select name, value 
        from  V$SES_OPTIMIZER_ENV 
        where sid=54 
           and name='hash_area_size';

NAME                                     VALUE
—————————————- ————————-
hash_area_size                           100000

Source: http://oracleinaction.com/other-session-params/

Yes, there is a way to check this.

You can query V$PARAMETER with this SQL:

SELECT name, value
  FROM v$parameter
 WHERE name like 'commit_write'
;

NAME                 VALUE
-------------------- --------------------
commit_write         (null)

Afterwards change the parameter on session basis:

ALTER SESSION SET commit_write = 'IMMEDIATE';

And query v$parameter again:

SELECT name, value
  FROM v$parameter
 WHERE name like 'commit_write'
;

NAME                 VALUE
-------------------- --------------------
commit_write         IMMEDIATE