Phase 3: Replaying the Workload
Since
my target database has now been reset to its prior state just before workload
capture was initiated and all my P+1 changes are now in place, at last I’m
ready to initiate the replay of the workload. I’ll use EM Database Control to
initiate the replay, as shown in Figure 2.4.1
below.
Once
I’ve selected a directory that already contains a captured workload, Oracle 11g
makes sure that I’ve reviewed all required prerequisites for a successful
replay, including what external references (e.g. external files and
directories) need to be resolved before proceeding, as shown in Figures 2.4.2 and 2.4.3 below.
Figure 2.4.2: Workload Replay: Confirming Prerequisites
Figure 2.4.3: Workload Replay: Confirming References to
External Systems
Once
all prerequisites have been confirmed, it’s time to set up the actual EM task
that will perform the replay. Figure 2.4.4
shows how I set up the basics for this task ...
Figure 2.4.4: Workload Replay: Setting Up Replay Task
... and
Figure 2.4.5 shows how I remapped
the current connection strings generated during the initial workload capture so
that the identical connection strings are used during this database replay
operation.
Figure 2.4.5: Workload Replay: Setting Up Connection Strings
As I
described in the Database Replay primer article, Oracle 11g allows me to alter
the frequency at which a workload is played back with extreme granularity. To
keep this demonstration simple, I’ve accepted the default options shown in Figure 2.4.6.
Figure 2.4.6: Workload Replay: Customizing Replay Options
It’s
now almost time to start the Workload Replay
Client (WRC) to play back the previously captured workload. As Figure 2.4.7 illustrates, my next step is
to start the WRC with the appropriate parameters and then return to this screen
and select the Next button to initiate the workload’s automatic replay:
Figure 2.4.7: Workload Replay: Initiating Workload Replay
Clients
I’ll
start the replay session by opening a terminal session and invoking the WRC
client executable. Note that I first changed my present working directory to /home/oracle/DBRControl before starting up
the WRC:
$> wrc system/oracle@orcl mode=replay replaydir=.
Workload Replay Client: Release 11.1.0.6.0 - Production on Thu May 22 19:28:59 2008
Copyright (c) 1982, 2007, Oracle. All rights reserved.
Wait for the replay to start (19:28:59)
...
Returning
to EM Database Control, I simply click on the Next button, and Oracle 11g
acknowledges that it has taken control of any active database replay operations
...
Figure 2.4.8: Workload Replay: Controlling Replay Operations
... and
that’s also reflected from within the terminal sessions themselves.
Wait for the replay to start (19:28:59)
...
Replay started (19:31:17)
Back
at EM Database Control, the status of the database replay operation is
constantly being monitored ...
Figure 2.4.9: Workload Replay: Monitoring Active Replay
Operations
..;
until the replay operation is completed.
Wait for the replay to start (19:28:59)
...
Replay started (19:31:17)
Replay finished (19:37:02)
Figure 2.4.10: Workload Replay: Completed Replay Operation
» 
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