Migrating from Oracle 11g to Oracle 19c involves a series of steps, including upgrading the database and performing data migration.

Migrating from Oracle 11g to Oracle 19c involves a series of steps, including upgrading the database and performing data migration. Here are the general steps involved:

Perform a full backup of your Oracle 11g database.

Install the Oracle 19c software on your server.

Create a new Oracle 19c database instance.

Upgrade the Oracle 11g database to the Oracle 19c version using the Database Upgrade Assistant (DBUA) tool. Here are the steps:

a. Launch the DBUA tool and select the option to upgrade an existing database.

b. Select the Oracle 11g database that you want to upgrade.

c. Follow the prompts and select the appropriate upgrade options, including the database version and the components to upgrade.

d. Review the upgrade summary and click "Upgrade" to start the upgrade process.

e. Monitor the progress of the upgrade and resolve any issues that may arise.

Perform post-upgrade tasks, including updating the initialization parameters, reviewing the database settings, and ensuring that the database is functioning correctly.

Migrate the data from the Oracle 11g database to the Oracle 19c database. This can be done using several methods, including Oracle Data Pump, Oracle GoldenGate, and SQL*Plus.

Test the new Oracle 19c database to ensure that it is functioning correctly and that all data has been migrated successfully.

Here are some commands you may use for data migration:

Oracle Data Pump export from Oracle 11g:

expdp username/password@source_db directory=DATA_PUMP_DIR dumpfile=export.dmp logfile=export.log full=y

Here are some commands you may use for data migration:

Oracle Data Pump export from Oracle 11g:

expdp username/password@source_db directory=DATA_PUMP_DIR dumpfile=export.dmp logfile=export.log full=y

Oracle Data Pump import to Oracle 19c:

impdp username/password@target_db directory=DATA_PUMP_DIR dumpfile=export.dmp logfile=import.log full=y

SQL*Plus export/import:

exp username/password@source_db file=export.dmp log=export.log full=y imp username/password@target_db file=export.dmp log=import.log full=y

Note that the specific steps and commands may vary depending on your environment and specific requirements. It is recommended that you consult the Oracle documentation and seek assistance from an experienced Oracle database administrator (DBA) to ensure a successful migration.

After migrating from Oracle 11g to Oracle 19c, there are some post-migration steps that you should perform to ensure that your new database is properly configured and functioning correctly. Here are some general steps and commands that you can use:

Update initialization parameters: Review the initialization parameters for the new Oracle 19c database and update them as necessary. Some common parameters to check include MEMORY_TARGET, SGA_TARGET, PGA_AGGREGATE_TARGET, LOG_ARCHIVE_DEST_n, DB_RECOVERY_FILE_DEST, and DB_CREATE_FILE_DEST.

Update optimizer statistics: Gather optimizer statistics for all database objects using the DBMS_STATS package. You can use the following command to gather statistics for all objects in the database:

EXEC DBMS_STATS.GATHER_DATABASE_STATS;

Review database security settings: Check the database security settings to ensure that they are appropriate for your environment. This includes checking user privileges, roles, and passwords, as well as enabling appropriate auditing and security policies.

Perform a full database backup: Take a full backup of the new Oracle 19c database using RMAN or another backup tool. This ensures that you have a recoverable copy of the database in case of any issues.

Perform testing: Test the new Oracle 19c database to ensure that it is functioning correctly and that all data has been migrated successfully. This includes running queries and applications to ensure that they work as expected.

Monitor database performance: Monitor the performance of the new Oracle 19c database to ensure that it is meeting your performance requirements. Use the various Oracle performance monitoring tools, such as AWR reports, to identify and address any performance issues.

Ensure high availability: Configure high availability features such as Oracle Data Guard or Oracle RAC to ensure that your database is always available in case of any hardware or software failures.

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