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.Database can be restructuredwith modified or newtablespaces.Copying Data Datafiles can be defragmented.Same as for Export/Import.Database can be restructuredwith modified or newtablespaces.Ability to migrate specificsegments of a database.Can be used forrelease to release migration.Table 3 1 Comparing Migration MethodsPreparing to Migrate 3 7 A carefully designed series of tests, that will validate all stages of theDevelop a Testing Planmigration process, will ensure the success of the migration operation.The importance of such a test program should not be underestimatedTesting Before Migration A rigorous testing program, performed before moving your productionsystem to an Oracle7, Release 7.x database, will ensure that the finalmigration process will be well understood and predictable.Failure toperform a rigorous testing program is risky and may lead to unpredictableresults.Therefore, as much testing as possible should be completedbefore migrating to an Oracle7, Release 7.x database.Such preparationtesting must include the following types of tests: migration, minimal,functionality, integration, performance, and stress.Migration Testing Migration Testing involves planning and testing the migration pathfrom the source database to the new, Oracle7, Release 7.x database.Youmay choose to perform a full database export under the sourcedatabase and then perform a full database import to move your data tothe Oracle7, Release 7.x database.You may also choose to use theMigration Utility.These methods are discussed in Chapter 4 TheMigration Utility and Chapter 5 Migrating Using Export/Import .Regardless of what migration method you choose, you must establish,test, and validate a migration plan.Minimal Testing Minimal testing involves moving all, or portions, of your applicationon the source database to the Oracle7, Release 7.x database andrunning the application without enabling any new, Release 7.x features.Minimal testing is a very limited type of testing that does not revealpotential issues you may encounter under a production environment.However, any application startup or invocation problems will berevealed immediately.Functional Testing Functional testing is a set of tests in which new and existingfunctionality of the system are tested after migrating.Functionaltesting includes all components of the RDBMS system, networking, andapplication components.The objective of functional testing is todetermine if each component of the system functions as it didbefore migrating.3 8 Oracle7 Server Migration Integration Testing Integration testing tests the interaction of each component ofthe system." Pro*C/C++ applications running against the Oracle7 instanceshould be tested to ensure that there are no problems with thenew software." GUI interfaces should be tested with other components." Subtle changes in Oracle7, such as datatypes, data in the datadictionary (additional rows in the data dictionary, object typechanges, etc.) can have an effect all the way up to the front endapplication, regardless of whether the application is directlyconnected to the Oracle7 instance or not." If the connection between two components involves SQL*Net,that connectivity should also be tested as well as stress tested.Performance testing of an Oracle7, Release 7.x database compares thePerformance Testingperformance of various SQL statements in Release 7.x with thestatements performance in the source database.Before migrating toOracle7, you should understand the performance profile of yourapplication under the source database.Specifically, you shouldunderstand the calls the application makes to the database kernel.Suggestion: To thoroughly understand your application sperformance profile under the source database, enableSQL_TRACE and profile with TKPROF.For more information,see Oracle7 Server Tuning.Volume/Load Stress Volume and load stress testing tests the entire, newly migratedTesting database under high volume and loads.(Volume describes the amountof data being manipulated.Load describes the level of concurrentdemand on the system.) The objective of volume and load testing is toemulate how a production system might behave under variousvolumes and loads.Volume and load stress testing is crucial, but is commonly overlooked.Oracle has found that customers often do not conduct any kind ofvolume or load stress testing.Benchmarks that do not characterizebusiness applications are, instead, relied upon heavily.Benchmarks ofthe application should be conducted to uncover unknown problemsrelating to functionality, performance and integration.Preparing to Migrate 3 9 Once the source database has been successfully migrated to Oracle7,Release 7.x, you should test the data to ensure that all data is accessibleand that your applications function properly.You should alsodetermine if any database tuning is necessary.If possible, you shouldautomate these testing procedures.Your testing plan should be representative of the work performed atyour site.You should test the functionality and performance of all ofyour applications on your source production databases.Gatherperformance statistics for both normal and peak usage.Specific Pre and The following tests can assist you in tuning your SQL statements afteryou migrate to Oracle7, Release 7.x:Post Migration Tests" Gather performance statistics for each of your SQL statements.You should be able to write scripts to extract these statementsfrom your applications and run them against your productiondatabase." Use EXPLAIN PLAN to determine the execution plan Oraclefollows to execute each SQL statement.Use the INTO parameterto save this information in a table.After migrating, you can compare performance under Oracle7, Release7.x with your source database test results by completing thefollowing steps:1.Use EXPLAIN PLAN to determine the execution plan for eachstatement.Save this information in a new table.2.Compare the Oracle7, Release 7.x execution plans to the sourcedatabase execution plans.If you notice a difference, you shouldexecute the command in Oracle7, Release 7.x and compare thisperformance to the performance of the source database
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