IN_PARSE set to 'Y' but no sql id seen against the row in V$ACTIVE_SESSION_HISTORY

hi Friends,

This question is more from academic point of view.

When the load test is done from application i see that for more 40% of the rows where event is null and session_state='Y' i see IN_PARSE='Y' but i dont see any sql id in that row.

How to know what is causing this parsing?

11:58:00 SQL> select IN_PARSE,count(9) from TMP_ASH where sql_id is null and session_state='ON CPU' group by IN_PARSE;

I|       COUNT(9)

-|---------------

Y|           2975 <<

N|           4644

How to investigate the cause of this parsing further?

Regds,

Sachin