PURPOSE
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Prevent hangs in RAC due to high login rate and low cache setting of AUDSES$ sequence.  
Default of 20 is not adequate in many cases.

 
PROBLEM:
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The default setting for the SYS.AUDSES$ sequence is 20, this is too low for a RAC system
where logins can occur concurrently from multiple nodes.  During high login rate
such low value can cause slowness and even hangs. Some of the symptoms are:
 - Checkpoint not completing on all RAC nodes
 - Waits expire on row cache enqueue lock dc_sequences
 - RAC hangs due to QMON deadlocking

During those hangs session login is not possible (or *extremely* slow) due 
to extremely high contention on the above sequence.

SOLUTION:
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Manually increase that sequence cache on each affected database:

alter sequence sys.audses$ cache 10000;

This is fixed in 10.2.0.3 patchset. (Affected releases 9i to 10.2.0.2)

REFERENCES
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bug:4390868 
bug:2855838

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