Question

Oracle session is waiting on event : rdbms ipc message.
Due to this High REDO session.

Comments

In some rare cases this used to be a platform bug in 7.0 database version, not in the later versions. semtimedop will not return even if another process modifies the semaphore. So, generally, this event is an idle event and as such, should be ignored.

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Check this link http://orainternals.wordpress.com/2012/02/10/what-is-rdbms-ipc-message-wait-event/  should be helpful

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then why it is doing High Redo session?

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@Gaurav: It should not have any relation but check the following link (may be helpful but not sure) http://orainternals.wordpress.com/2008/07/07/tuning-log-file-sync-wait-events/

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@Gaurav: Is Your problem solved?