This pattern describes how to migrate an on-premises legacy Oracle 8i or 9i database to Amazon Relational Database Service (Amazon RDS) for PostgreSQL or Amazon Aurora PostgreSQL-Compatible Edition. 

AWS Database Migration Service (AWS DMS) doesn't support Oracle 8i or 9i as a source, so this pattern uses an intermediate Oracle database instance that's compatible with AWS DMS, such as Oracle 10g or 11g. It also uses the materialized views feature to migrate data from the source Oracle 8i/9i instance to the intermediate Oracle 10g/11g instance.

AWS Schema Conversion Tool (AWS SCT) converts the database schema, and AWS DMS migrates the data to the target PostgreSQL database. 

This pattern helps users who want to migrate from legacy Oracle databases with minimum database downtime. In this implementation, the downtime would be limited to the length of time it takes to create or validate all the foreign keys, triggers, and sequences on the target database. 

The pattern uses Amazon Elastic Compute Cloud (Amazon EC2) instances with an Oracle 10g/11g database installed to help AWS DMS stream the data. You can temporarily pause streaming replication from the on-premises Oracle database to the intermediate Oracle instance to enable AWS DMS to catch up on data validation or to use another data validation tool. The PostgreSQL DB instance and intermediate Oracle database will have the same data when AWS DMS has finished migrating current changes.

Prerequisites and limitations

Prerequisites 

• An active AWS account

• A source Oracle 8i or 9i database in an on-premises data center 

• AWS Direct Connect configured between the on-premises data center and AWS

• Java Database Connectivity (JDBC) drivers for AWS SCT connectors installed either on a local machine or on the EC2 instance where AWS SCT is installed

• Familiarity with using an Oracle database as an AWS DMS source

• Familiarity with using a PostgreSQL database as an AWS DMS target

Limitations 

• The database size limit is 64 TB

Product versions

• Oracle 8i or 9i for the source database

• Oracle 10g or 11g for the intermediate database

• PostgreSQL 10.17 or later

Architecture

Source technology stack  

• Oracle 8i or 9i database 

Target technology stack  

• Amazon RDS for PostgreSQL or Aurora PostgreSQL-Compatible

Target architecture

https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/migrate-from-oracle-8i-or-9i-to-amazon-rds-for-postgresql-using-materialized-views-and-aws-dms.html?did=pg_card&trk=pg_card