To find out which queries are running in database, login as SYS and issue the following query:

 

SELECT

a.USERNAME, a.STATUS, b.sql_text
FROM V$SESSION a INNER JOIN V$SQLAREA b
ON a.SQL_ADDRESS= b.ADDRESS;

 

V$SESSION view lists session information for each current session.

 

To see field-wise description for V$SESSION follow the link below:

V$SESSION

V$SQLAREA lists statistics on shared SQL area and contains one row per SQL string. It provides statistics on SQL statements that are in memory, parsed, and ready for execution.

To see field-wise description for V$SQLAREA follow the link below:

V$SQLAREA

This is what Oracle has to say about this error:

---

FRM-40502: ORACLE error: unable to read list of values.

Cause:  A fatal error occurred while trying to read a list of values.

Action:  Contact your DBA or an Oracle support representative.

Level:  >25

Type:  Error

---

I had not encountered this error till recent times. But it was today I had encountered this error. I was scratching my head as to what caused this error.

I was working with a form with 6i release, converted to 10g. In that while clicking F9 for LOV in one of the fields, I encountered this error. I started debugging the form, starting from Field, LOV, Record Group. There were no problems at first sight.

I copied the SQL query from the record group and ran it in SQL*Plus, there was no problems. The query was using some bind variables from inside the form. I had modified these fields with values.

I then tried to run exactly the same where clause of the query (I commented out the bind variables) and ran the form. Bingo! It worked and the FRM-4502 error suddenly is gone.

I then tried to run the previous query (with bind variables), now also the error did not came.

I suppose this error is due to the ID of the field with which Forms works rather than the name.

It made a super note for me today...

Hope if you are in same mood, use this logic to solve your problem.

Regards
Anantha