How can you migrate data from Oracle to MySQL with minimal downtime?

Carefully pay attention to the following aspects that are often missed when planning a migration: - Database and software versions - Licensing and End of Life Support - Available Network bandwidth to replicate/move the data - Migration team skillet: both experience and certifications - Migration team Roles & Responsibilities across organizations (customer, vendor, third parties) - Migration and rollback strategies - Migration run books expectations - Post migration activities and hyper care.

Planning and assessment - Conduct a comprehensive assessment of the source Oracle database, including schema, data types, and dependencies. - Identify and map compatible MySQL data types for Oracle data types. - Develop a migration plan that outlines the steps involved, timelines, and resources required. - Evaluate the impact of the migration on production systems and users. - Determine the acceptable level of downtime.

One of the tools that can be used to migrate data between both RDBMSs is Oracle Golden Gate, which can keep synchronizing data until the day the DB can start working from the MySQL destination. It's very important to test performance considering the different nature of both engines, thus the different possible behavior between Oracle DB and MySQL.

Follow the simple steps: 1. Planning: Assessment , Schema mapping, Data Mapping, ER Diagrams, agree on downtime window (low traffic times /scheduled maintenance) 2. Data Pre-processing: Cleanup, Schema changes (removing unsupported features), Robust ETL 3. Testing: two cycles of data migration (Test environments)- check data integrity 4. Synchronization: Delta data capture for changes during migration cycle : use Oracle Change data capture or custom scripts 5. Minimize downtime: Setup MySQL as hot standby, Do parallel migration processing, use ‘mysqldump’ utility to perform final data migration during downtime Finally have a cutover, monitor & optimize post migration and have a well-defined rollback plan with meticulous documentation.

Goldengate 23c is the quickest way of doing this. Also you may take advantage of the free version which allows you to essay what you’re doing.

Minimizing downtime is to keep the Oracle database online and in use while the initial data migration and synchronization take place. Once the MySQL database is fully synchronized and you have verified that everything is working as expected, you can perform the cutover. This approach minimizes the downtime to just the final synchronization and switchover period.

Migrating data from Oracle to MySQL with minimal downtime can be a complex process, but with careful planning and the right strategies, it's possible to achieve a smooth transition. Here are the key steps and strategies to consider: Planning and Assessment: Data Schema Mapping: Data Extraction: Data Transformation: Load Data into MySQL: Data Synchronization: Testing and Validation: Switch Over: Monitoring and Optimization: Backup and Rollback Plan: Documentation: Remember that the key to minimizing downtime is thorough planning, meticulous testing, and careful execution. Depending on the complexity and size of your database, you may also consider using specialized migration tools.

In a previous role, my team faced the challenge of migrating from Oracle to MySQL. Recognizing the critical nature of downtime, we adopted a 'Zero-Downtime Migration' strategy using a phased approach. We first moved non-essential tables and tested them, while using real-time data replication to keep both databases in sync. Addressing data type compatibility was another crucial step; for example, we converted Oracle 'BLOB' types to MySQL compatible 'TEXT' types well in advance. These actions saved us critical hours during the final migration. We conducted most activities during weekends to minimize operational impact. This careful planning and strategic timing not only reduced performance issues but also minimized downtime.

Testing and validation - Create a sandbox environment that mirrors the production environment. - Perform a full migration of the data to the sandbox environment. - Conduct thorough testing to ensure data accuracy, completeness, and functionality. - Validate the performance of the migrated database. - Make necessary adjustments to the migration plan based on testing results.

In our Oracle to MySQL migration, we employed a 'Blue-Green' deployment model for testing. Two mirrored production environments were maintained: one with Oracle and another with MySQL. We prioritized using MySQL Workbench for initial migration and Oracle SQL Developer for verification. This dual-tool strategy enabled higher confidence in data consistency. Before switching to MySQL, a thorough suite of automated tests validated data integrity and application behavior. Stress tests were also run to optimize query performance and resource utilization, ensuring a smooth transition. This validated the effectiveness of our migration strategy while minimizing downtime.

Although it is mentioned a couple of times, I want to emphasize the importance of stress testing. The two databases are different in fundamental ways, and even if the Oracle database is not heavily loaded, you can't just switch to the same server configuration and assume it'll work the same way. You need to do thorough performance testing on the proposed final configuration, with the full set of data, to ensure there are no bottlenecks. And if there are, apply fixes and test again before doing the actual migration.

Data migration - Utilize a migration tool or script to automate the data transfer process. - Employ incremental or parallel migration methods to minimize downtime. - Schedule the migration during off-peak hours to reduce impact on users. - Monitor the migration process closely to identify and resolve any issues.

In our recent Oracle to MySQL migration, a meticulous approach was taken. To start, both the Oracle and MySQL databases were backed up. Triggers and constraints were temporarily disabled on the MySQL end to speed up data migration. To cope with Oracle's PL/SQL procedures, we created equivalent MySQL stored procedures. Two migration methods were employed: a full migration for smaller tables and incremental migration for larger datasets, thus minimizing downtime. During this period, real-time monitoring was critical to swiftly handle any anomalies or data corruption. After data migration, re-enabling and optimizing the MySQL triggers and constraints was not just a formality; it was an essential step to assure data integrity and performance.

Cutover and validation - Once the data migration is complete, perform a final round of testing to ensure data integrity. - Cutover to the new MySQL database. - Monitor the production system for any performance or stability issues. - Conduct post-migration audits to verify data accuracy and completeness. Post-migration activities - Update any applications or scripts that rely on the database. - Decommission the source Oracle database. - Document the migration process for future reference.

In my role as CTO, overseeing data migrations is routine, and verifying the migration is crucial but often overlooked. While tools like MySQL Diff and Oracle Data Compare are essential, human validation is just as important. Post-migration, we implemented unit tests to confirm application logic was unaffected. We also deployed A/B testing to ensure the new MySQL-based solutions were performing well. Special attention was given to roles and permissions, to avoid any security risks. Verification should be as comprehensive as the initial planning phase; it's your safety net for ensuring a successful migration.

I've been through quite a few of these types of migrations. In my experience, the schema and the data are the easy part. It might take a bit of fiddling, but you can get that stuff ironed out quickly. The truly painful aspects of these projects are caused by the internal and procedural differences between the source and the target. In this case, we are talking about sequences, triggers, optimizer directives, packages and stored procedures, and replication. This is where the lion's share of the work will be and you will definitely want to do a full regression against the new database. Sometimes that's the fastest and easiest way to discover what you have missed (and you will have missed something).

A bit contentious...but why migrate to MySQL? Surely migrating to PostgreSQL (or even MariaDB) would be a more relevant article as they are both OSS databases like MySQL? Remember Oracle owns BOTH OracleDBMS and MySQL so I would hope Oracle would have developed a lot of tooling to do this type of migration? LinkedIn: Little disappointed you are creating an article about 2 products from the same company, but your AI might have missed that. Little history timeline 1995 - MySQL created by MySQL AB in Sweden 2008 - Sun Microsystems buy MySQL AB 2010 - Oracle buys Sun Microsystems (27th January) 2010 - (28th January) Founder of MySQL AB forks codebase to produce MariaDB