Only one workload capture can be performed at any given time. By default, once the workload capture begins, any database instance that are in RESTRICTED mode will automatically switch to UNRESTRICTED mode, and normal operations can continue while the workload is being captured. To avoid this problem, consider restarting the database in RESTRICTED mode using STARTUP RESTRICT, which will only allow the SYS user to login and start the workload capture. Otherwise, transactions performed by these user sessions will not be replayed properly in subsequent database replays, because only the part of the transaction whose calls were executed after the workload capture is started will be replayed. Once the database is restarted, it is important to start the workload capture before any user sessions reconnect and start issuing any workload. In this case, you should consider starting the workload capture at an earlier time, so that the database can be restarted at a time that is less disruptive. However, to avoid service interruption during normal business hours, you may not want to restart the database during this time. For example, you may want to capture a workload that begins at 8:00 a.m. On a busy system, it is normal to see some replay divergence, but the replay can still be used to perform meaningful analysis of a system change if the diverged calls do not make up a significant portion of the replay in terms of DB time and other such key attributes.īefore restarting the database, determine an appropriate time to shut down the production database before the workload capture when it is the least disruptive. Any subsequent transactions with dependencies on the incomplete transactions may also generate errors during replay. This may result in undesired replay divergence when the workload is replayed. Ongoing transactions will thus not be replayed properly, because only the part of the transaction whose calls were captured will be replayed.
If the database is not restarted before the capture begins, transactions that are in progress or have yet to be committed will not be fully captured in the workload. While this step is not required, Oracle recommends that the database be restarted before capturing the workload to ensure that ongoing and dependent transactions are allowed to be completed or rolled back before the capture begins.
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