5
After Migrating the Database

This chapter discusses the steps to perform after you have completed migrating from an earlier version to Oracle8 using either the Migration Utility or the Export/Import method of migration. This chapter elaborates on the migration process "Step 6: Tune and Adjust the New Production Database" on page 1-3.

Topics in this chapter include the following:

Back Up the Oracle8 Database

After completing the migration of the production database, make sure you have a complete backup of the newly migrated database. This backup must be complete, including all datafiles, control files, online redo log files, parameter files, and SQL scripts that create objects in the new database. (A full database export or a cold backup is required, because a hot backup cannot afford full recoverability.) This backup can be a return point, if needed, in case subsequent steps affect the newly migrated database adversely. See Oracle8 Server Backup and Recovery Guide and Oracle8 Server Administrator's Guide for details.

Note: Using the Migration Utility transforms the source database, which therefore ceases to exist except for the backup created under "Step 4: Preserve the Oracle7 Source Database" on page 3-10. The backup created in those procedures, however, can serve also as the first Oracle8 backup for an Oracle8 recovery of the newly migrated database.

Test the Database and Compare Results

Test the Oracle8 database using the testing plan developed in Step 1 of the migration procedure, as described in "Develop a Testing Plan" on page 2-9. Compare the results of the test with the results obtained with the original database and make certain the same results are achieved.

Generally, performance with any Oracle8 database should be as good as, or better than, performance with the source database. If you notice any decline in database performance with Oracle8, verify that initialization parameters are set properly. Also, see Oracle8 Server Tuning for database tuning information.

Besides testing the migrated test database, you might run the original source database and the newly migrated Oracle8 database concurrently for a time, to make sure that the new database is correctly configured and functioning properly. You would need to modify the Oracle configuration (not described in this manual) to run both databases concurrently. Of course synchronized updates would need to be made to both databases, ideally as part of an automated process.

Tune the Target Database

If you feel that performance of the migrated database could be improved tune the database. Refer to Oracle8 Server Tuning for detailed information.

Most of the methods used to tune Oracle7 databases and related applications either have the same effect on or are unnecessary for Oracle8 databases. Therefore, any actions you took to tune your source database and applications should not impair the performance of the target database.

Add New Features as Appropriate

Appendix A, "Oracle8 Enhancements", describes many of the new features available in Oracle8. You should determine which of these new features can benefit the design of the database and applications and develop a plan for incorporating them. You do not, however, have to make any immediate changes to begin using your target database. You may prefer to introduce these enhancements into your database and corresponding applications gradually.

Chapter 6, "Upgrading Oracle7 Applications", describes how you can enhance your applications to begin taking advantage of these new features. You should already have tested your applications and successfully run them with the target test database (possibly running in special Oracle7 compatibility mode).

Develop New Administrative Procedures as Needed

After familiarizing yourself with the new target database features, you should review your database administration scripts and procedures to determine whether any changes are necessary.

You should coordinate your changes to the database with the changes that need to be made to each application. For example, by enabling integrity constraints in the database, you may be able to remove some of this data checking from your applications.

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5 After Migrating the Database