Oracle 11g : Real Application Testing ( RAT )

As per my understanding  RAT is same like Metric Baseline or Database Replay feature which we had discussed in OEM12c presentation  and it is like a  recorder, allowing workload to be captured and replayed for testing and benchmarking purposes.  RAT captures transactions against the Oracle database (as made by an application) and allows them to be easily tested. 

·         RAT Includes:

1.        Database Replay

2.        SQL Performance Analyzer

·         Database Replay

§  Captures database workload on production system

§  Replays captured workload on test system

§  Optionally includes concurrency and timing characteristics

§  Generates reports and recommends changes

·         SQL Performance Analyzer

§  Identifies performance divergence between workloads on source and target platforms

§  Generates tuning recommendations

Capture Workload

1.        Create an operating system directory

                                   [oracle@nitiserver]$ mkdir -p /cfspshr/backup/oracle/testp/oracle/testp1/rat

2.        Create an Oracle directory

SQL> CREATE DIRECTORY dir1 AS ‘/cfspshr/backup/oracle/testp/oracle/testp1/rat';

Directory created.

3.        Start the capture process

BEGIN

  DBMS_WORKLOAD_CAPTURE.START_CAPTURE (name => 'May12_Peak',

                           dir => 'RAT',

                           duration => 600);

END;

/

PL/SQL procedure successfully completed.

4.        Run the workload - Do some random works and transactions etc. Finish the capture process

SQL> BEGIN dbms_workload_capture.finish_capture; END;

  2  /

PL/SQL procedure successfully completed.

OEM Method :

Database Replay Database Replay allows workloads to be captured from production systems and re-executed with high fidelity on test copies of production databases. This enables detailed analysis of how the proposed changes may affect production systems; for instance, patching or upgrading database software. Page Refreshed May 21, 2012 6:24:36 AM EDT

Task List Expand All | Collapse All Task Name Description Go to Task Capture Production Workload Initiate or schedule a workload capture, export AWR data after capture, and copy captured files to the workload staging area. Capture Workload Capture a workload from the production environment. This can be scheduled to accommodate a database restart if desired. Export AWR Data Export AWR data to provide a better performance comparison between captured and replayed workloads. Copy to Workload Staging Area Copy captured files away from production to the workload staging area for later preprocessing. For a cluster database, captured files from different database instances can be consolidated in the workload staging area. Prepare Test Database Set up a test database from production, upgrade or otherwise modify the test database, and isolate the test database prior to replay. Set Up Test Database Clone the production database to a test environment. The test database should be restored to match the capture database at the start of capture. You may make any changes to the test environment as needed. Isolate Test Database Isolate the test system from production environment prior to the workload replay. This task must be performed on the test database target. Prepare for Replay Prepare the workload capture files for replay (preprocess), copy the preprocessed workload files to the workload staging area, deploy the Replay Clients, and copy the preprocessed workload files to the Replay Client hosts. Preprocess Workload Preprocessing prepares a captured workload for replay. You must do this once for every captured workload. Preprocessing is best performed in the test database. The captured workload must be accessible from the test database. Copy to Workload Staging Area Copy preprocessed workload files to the workload staging area. The preprocessed workload files must be accessible by the database server and the Replay Clients during replay. Deploy Replay Clients Deploy the Replay Client to one or more host machines. Replay Clients are used to replay the preprocessed workload. Copy Workload to Replay Client Hosts Copy the preprocessed workload to one or more Replay Client host machines. Each Replay Client must be able to access the preprocessed workload during replay. Replay Workload on Test Database Set up the workload replay on the test database, copy the replay results to the workload staging area, and analyze the results. Replay Workload Replay the preprocessed workload on a test copy of the production database. Copy to Workload Staging Area Copy replay results to the workload staging area for comparision analysis with future replays. Analyze Results Analyze the effects of changes on workload performance.

In a sense, RAT has many of the same features as the Quest "Benchmark Factory" product.