Oracle database licensing is one of the largest IT cost centers for many organizations. Migrating Oracle to AWS—whether to Aurora PostgreSQL, RDS, or staying on Oracle with optimized licensing—can reduce database costs by 60-80% while improving availability and operational efficiency.
Why Migrate Oracle to AWS?
Organizations migrate Oracle databases to address:
- Licensing costs: Oracle licensing can exceed $50,000 per CPU core annually
- Vendor audits: Complex licensing creates audit exposure
- Operational burden: Self-managed Oracle requires specialized DBA skills
- Limited scalability: Scaling Oracle often means expensive hardware upgrades
- High availability costs: RAC and Data Guard add significant licensing
Cost Comparison
| Scenario | Oracle On-Prem | AWS Target | Savings |
|---|---|---|---|
| 4-core database | ~$200K/year | Aurora PostgreSQL: ~$40K/year | 80% |
| Enterprise Edition + RAC | ~$400K/year | Aurora: ~$60K/year | 85% |
| Standard Edition | ~$80K/year | RDS PostgreSQL: ~$20K/year | 75% |
Migration Paths
Oracle to Aurora PostgreSQL
Best for: Maximum cost savings, organizations willing to invest in schema conversion
Benefits:
- No Oracle licensing—open source PostgreSQL
- Aurora’s MySQL/PostgreSQL compatibility with 3-5x performance
- Automatic scaling, high availability, managed backups
- 60-80% cost reduction typical
Considerations:
- Requires schema conversion (stored procedures, packages, data types)
- Application changes may be needed for Oracle-specific SQL
- Testing investment for functional validation
Oracle to Aurora MySQL
Best for: Applications with simpler schemas, MySQL expertise in-house
Benefits:
- No Oracle licensing
- MySQL compatibility with Aurora performance
- Large ecosystem of tools and expertise
Considerations:
- More significant schema differences than PostgreSQL
- Stored procedure conversion more complex
- Best for newer applications without deep Oracle dependencies
Oracle to RDS Oracle
Best for: Minimizing changes, short timelines, or complex Oracle dependencies
Benefits:
- No schema conversion required
- Managed infrastructure (patching, backups, HA)
- BYOL or license-included options
- Fastest migration path
Considerations:
- Oracle licensing costs continue (though often reduced)
- May be stepping stone to further modernization
- Good for “rehost then optimize” strategy
Oracle to DynamoDB
Best for: Specific workloads suited to NoSQL patterns
Benefits:
- Serverless, scales automatically
- Single-digit millisecond performance
- No database administration
Considerations:
- Requires data modeling changes
- Not suitable for complex relational queries
- Best for specific use cases (session stores, catalogs, gaming)
AWS Migration Tools
AWS Schema Conversion Tool (SCT)
Analyzes Oracle schemas and converts to target database:
- Assessment report: Identifies conversion complexity
- Automated conversion: Transforms ~80-95% of schema objects
- Action items: Flags objects requiring manual conversion
- Code conversion: Handles stored procedures and functions
AWS Database Migration Service (DMS)
Migrates data with minimal downtime:
- Full load: Initial bulk data migration
- CDC (Change Data Capture): Ongoing replication during transition
- Minimal downtime: Cutover in minutes, not hours
- Validation: Ensures data integrity post-migration
Migration Workflow
- Assessment: SCT analyzes source database, generates report
- Schema conversion: SCT converts schema, manual work for exceptions
- Data migration: DMS performs full load and CDC
- Application testing: Validate application functionality
- Cutover: Switch applications to AWS target
- Validation: Confirm data integrity and performance
Handling Oracle-Specific Features
PL/SQL Packages and Procedures
- SCT converts most PL/SQL to PL/pgSQL automatically
- Complex packages may require manual refactoring
- Consider converting to application code (Lambda, Java) for maintainability
Oracle-Specific SQL
| Oracle Feature | PostgreSQL Equivalent |
|---|---|
| ROWNUM | LIMIT / OFFSET |
| NVL() | COALESCE() |
| DECODE() | CASE statement |
| CONNECT BY | WITH RECURSIVE |
| Sequences | SERIAL / SEQUENCES |
| DUAL table | Not needed |
Advanced Features
- RAC: Aurora provides multi-AZ and read replicas natively
- Data Guard: Aurora replication is automatic and synchronous
- Partitioning: PostgreSQL native partitioning or Aurora features
- Advanced Security: AWS KMS, IAM, VPC for security
Migration Timeline
| Phase | Duration | Activities |
|---|---|---|
| Assessment | 2-4 weeks | Schema analysis, complexity scoring, planning |
| Schema conversion | 2-8 weeks | SCT conversion, manual remediation |
| Data migration setup | 1-2 weeks | DMS configuration, full load |
| Testing | 2-4 weeks | Application testing, performance validation |
| Cutover | 1 day | Final sync, DNS switch, validation |
Total: 8-20 weeks depending on database complexity
Case Study: Healthcare Oracle Migration
A healthcare organization migrated their core Oracle database to Aurora PostgreSQL.
Before:
- Oracle Enterprise Edition with RAC
- 12 cores, $600K annual licensing
- 4 dedicated DBAs
- 8-hour maintenance windows monthly
After:
- Aurora PostgreSQL Multi-AZ
- $80K annual AWS costs
- 1.5 DBAs (others redeployed)
- Zero planned downtime
Results:
- 87% cost reduction
- Automatic scaling handles 5x traffic spikes
- Point-in-time recovery to any second
- Eliminated Oracle audit exposure
Common Concerns
Will performance suffer?
Aurora PostgreSQL often outperforms Oracle for most workloads. Proper indexing and query optimization during migration typically improves performance.
What about Oracle-specific features we depend on?
SCT identifies dependencies and provides conversion paths. Most features have PostgreSQL equivalents. Complex cases can be handled in application code.
How do we handle the skills gap?
PostgreSQL skills are more available and less expensive than Oracle DBA expertise. Training existing staff on PostgreSQL is straightforward.
What if migration fails?
DMS maintains continuous replication during migration. Rollback is simply pointing applications back to Oracle source. Parallel run minimizes risk.
Get Your Free Database Assessment
Our free assessment analyzes your Oracle databases and recommends the optimal migration path:
- Database inventory with complexity scoring
- Migration path recommendation per database
- Cost projection comparing current state to AWS targets
- Timeline and resource estimate
Related Resources
- Application Modernization to AWS — Complete modernization guide
- Replatform Migration — Database replatforming strategies
- .NET Modernization — Modernizing .NET applications that use Oracle