The time for this phase depends on how many locks must be
recovered, as well as whether the rebuild process involves a single surviving node
or multiple surviving nodes. Oracle speeds the lock remastering process by
allowing optimization of lock master locations in the background while users are
accessing the system. In a two-node cluster, node failure leaves a single surviving
node that acts as a dictator and processes the lock operations very quickly.
Instance recovery
Once the lock database is rebuilt, the redo logs from the failed instance perform
crash recovery. This is similar to single-instance crash recovery??”a rollforward
phase followed by a nonblocking, deferred rollback phase. The key difference is
that the recovery isn??™t performed by restarting a failed instance. Rather, it??™s performed
by the instance that detected the failure.
272 | Chapter 11: Oracle and High Availability
While Real Application Clusters recovery is in progress, clients connected to surviving
instances remain connected and can continue working.
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