Last updated on DECEMBER 06, 2016
Applies to:Oracle Database - Enterprise Edition - Version 10.2.0.4 and later
Information in this document applies to any platform.
***Checked for relevance on 09-Sep-2016***
The purpose behind creating this article is to give a detailed information about using the Database Replay feature before upgrading from 10.2.0.4 to 11g, supported by a life example.
Before making changes, such as hardware or software upgrades, companies typically conduct extensive testing to validate the changes. However, when the change is made on the production system, unexpected problems are often encountered because the testing was not performed with a workload that was a good representation of the production environment. Tools are available in the market to construct "synthetic workloads" involving multiple users. However, they are not able to adequately simulate the complexities of a real-world workload, such as interactions between concurrent activities and unpredictability of the workload profile.
DB replay does this by capturing a workload on the production system with negligible performance overhead ( My observation is 2-5% more CPU usage ) and replaying it on a test system with the exact timing, concurrency, and transaction characteristics of the original workload. This makes possible complete assessment of the impact of the change including undesired results; new contentions points or performance regressions. Extensive analysis and reporting ( AWR , ADDM report and DB replay report) is provided to help identify any potential problems, such as new errors encountered and performance divergences. Thus using Database Replay, businesses can incur much lower costs and yet have a high degree of confidence in the overall success of the system change and significantly reduce production deployment.
The ability to replay the workload, however, has been introduced in Oracle Database 11g (11.1). This has been done so that when you upgrade from Oracle Database release 10.2.0.4 to 11.1 or 11.2, you can use the Database Replay feature to help with the upgrade.
Actually, the Capture feature has started to be included starting from 10.2.0.4 (DBMS_WORKLOAD_CAPTURE) but the Database Replay complete functionality started in 18.104.22.168 and up. Thus you can use the capture process to capture the workload in 10.2.0.4 and then on a test environment replay the captured workload into 11g database before doing the upgrade.
The workload that has been captured on Oracle Database release 10.2.0.4 and higher can also be replayed on Oracle Database 11g release. So it simply mean NEW patch set 10.2.0.4 will support capture processes.
The database capture functionality was introduced with 10.2.0.4. However, patches are available for some earlier versions.
Please refer to:
Using Real Application Testing Functionality in Earlier Releases (Doc ID 560977.1)
Note also that Database Capture and Replay is part of the Real Application Testing (RAT) option which needs a separate license.
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