Governor=Enabled
Governor=Disabled
Enables or disables the replication governor.
Applicable to: Standby database
Required or Optional: Optional
Default Value: Governor=Enabled
The purpose of the replication governor is to coordinate database
replication operations automatically between the master and the
standby databases. With the replication governor enabled, you can
effectively ensure that:
o The master and standby databases do not get too far out of
synchronization with respect to each other
o The performance of the master database does not deviate
greatly from that of the standby database
o The peak-time database requirements are handled automatically
and dynamically by the Hot Standby software
The replication governor allows the ALS process on the master
database and the LRS process on the standby database to
automatically choose the synchronization mode that provides
the best performance and ensures database replication
synchronization.
To use the replication governor most effectively, ensure
the Governor qualifier is Enabled and include the
Synchronization=Cold qualifier when you start replication
operations on the standby database. (Also, see the
Synchronization qualifier discussed later in this Help topic.)
Oracle Corporation recommends that you set the Synchronization
qualifier to Cold mode. This setting is most effective because
of the way the LRS process monitors its replication workload from
the master database, as described in the following table:
If . . . Then . . .
The replication The LRS process automatically upgrades
workload increases at to a stronger synchronization mode. For
a rate that prevents example, if the Synchronization qualifier
the standby database was originally set to Cold mode, the LRS
from keeping up with would change the synchronization mode to
the master database Warm (or higher, as required).
The replication The LRS process automatically downgrades
workload shrinks or weakens the synchronization mode.
However, the synchronization mode is
never weaker than the mode (Commit, Hot,
Warm, Cold) that you specify with the
Synchronization qualifier.
Because the synchronization mode changes dynamically, the LRS
process transmits the current synchronization mode to the ALS
process (on the master database) at every checkpoint interval
(see the Checkpoint qualifier earlier in this Help topic). For
example, if the replication governor upgrades the synchronization
mode from Cold to Warm, the LRS process transmits the information
to the ALS process. Then, the ALS process uses the stronger mode
on all subsequent messages to the standby database. (Note that
the LRS process maintains a different synchronization mode for
each master database node.)
Use the RMU Show Statistics command on the master database to
monitor the dynamically changing synchronization mode required by
the actual work load, and compare that to the mode you specified
with the Synchronization qualifier.
Recommendation: Oracle Corporation recommends that you do not use
the Governor=Disabled setting until the replication performance
is well understood and constant. Severe performance deviations on
the master database could stall or stop the database replication
operations.