Question: I just upgraded from 10g to 11g
and I now see poor performance. My AWR report looks like this,
with high Oracle virtual circuit wait events:
Top 5 Timed Foreground
Waits Time(s) Avg wait (ms) % DB time Wait Class
virtual circuit wait 95,038 16,056 169
is a virtual circuit, and why is my instance waiting on it?
Answer: First check MOSC Note 1225943.1
titled High virtual circuit waits after upgrade. A
high "virtual circuit wait" wait event has two display parameters,
P1 ("the circuit#") and P2 ("the type").
virtual circuit# being waited on
type of operation the session is waiting for
Beware, the virtual circuit wait has been associated with the
use of shared servers (The multi-threaded server, or MTS).
Oracle DOES NOT recommend using shared servers, except as a stopgap
measure because dedicated database connections are faster and
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