Concurrent Requests hanged.

Dear All Experts,

EBS R12.1.3 PCP 2 nodes shared appl_top

11.2.0.2 DB RAC 2 nodes

RHEL 5.5

We faced issue that all concurrent request were hanged till one hour and after this every thing became normal , all requests completed normal .

When we stepped in to trouble shoot we found following in top 5 events

enq: TX - row lock contention

123,520

104

1

3.66

Application

we found that this lock was on   FND_CONCURRENT_REQUESTS table.

i am uploading output of following query

SELECT  C.SQL_TEXT,

        B.NAME,

        COUNT(*),A.session_id,

        SUM(TIME_WAITED)

FROM    v$ACTIVE_SESSION_HISTORY A,

        v$EVENT_NAME B,

        v$SQLAREA C