Tamilselvan,

Yes, "null event" is a valid idle wait event that can potentially occur when a piece of code (explicit or implicit) calls the wait interface without an event id. However, for 9i version of oracle, there is a known bug that has been fixed in 9.2.0.4 where oracle has replaced "null event" with "unspecified event" to indicate a wait state
where no named event has been supplied.
The individual who has posted below has the problem with the "null event" wait event in 9.2.0.1 and that's one of the versions of 9i being affected.

Thanks!

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