Choosing an Oracle to PostgreSQL converter is less about picking a tool and more about understanding your database, your constraints, and how much automation you truly need. The process starts with a self-assessment. Before you even look at tools, you need a clear picture of what you are migrating. A small Oracle database with mostly tables and basic SQL is straightforward—practically any converter will handle it. But once you introduce PL/SQL packages, triggers, partitions, complex datatypes like XMLType or user-defined objects, or if your data volume climbs past hundreds of gigabytes, the choice becomes more strategic. The more Oracle-specific your environment is, the more capable and intelligent your converter must be.
Define the Scope and Complexity of Oracle Database
With a baseline understanding of your database complexity, you can begin evaluating what the tools actually offer. All converters promise schema conversion and data migration, but the difference lies in how reliably they translate Oracle features into PostgreSQL equivalents. For instance, you want a tool that can map datatypes accurately, translate PL/SQL into PL/pgSQL without breaking logic, and handle large objects without choking.
Before choosing a tool, assess what needs to be migrated:
- Database Size. For small (<50GB) databases most migration tools will work fine. For medium size (50–500 GB) choose tools that support multi-threading and bulk copy. For large size(>500 GB) look for proven high-volume migration support, resumable loads, and parallelism.
- Schema Complexity. Identify Oracle features being used in the source database (PL/SQL packages, procedures, triggers, materialized views, partitions, clusters, etc). Not all converters support PL/SQL translation or complex types. PostgreSQLequivalentsoftenrequirerewriting.
- Application Dependencies.Determine what applications connect to the DB. Do they use Oracle-specific SQL?The more Oracle-centric your applications are, the more advanced translator your converter must be.
Evaluate the Features of Migration Tools
When comparing Oracle to PostgreSQL migration tools, check for the following:
| Feature | Why it’s important |
| Schema conversion | Converts tables, indexes, constraints, data types |
| PL/SQL → PL/pgSQL translation | Automatic procedure translation saves huge effort |
| Data migration | High-speed extract and bulk-load into PostgreSQL |
| Error handling and detailed logs | Needed to fix incompatibilities |
| Rollback/resume | Prevents re-starting long migrations |
| Support for LOBs (CLOB/BLOB) | Many tools fail on these |
For enterprise databases you should also look for these advanced features:
- Automated mapping of Oracle functions to PostgreSQL functions
- Conversion of Oracle packages to schema-level functions
- Advanced datatype mapping (OBJECT, COLLECTION, REF CURSOR)
- Parallel data loading
- Migration of users/roles/permissions
- CDC (Change Data Capture) or live replication for zero-downtime cutover
Some converters automatically replace Oracle built-in functions with PostgreSQL analogs, reorganize packages into schemas and functions, or flag pieces of logic that require manual rewrites. If downtime is a concern, you’ll want a converter that supports parallel data loading or even change-data-capture so you can keep Oracle and PostgreSQL in sync until cutover.
Determine the Type of Migration Tool You Need
Once you understand the feature landscape, think about which type of tool best fits your needs. Commercial suites—like Oracle-to-PostgreSQL by Intelligent Converters or AWS’s Schema Conversion Tool—are designed for enterprises, where PL/SQL is heavy and uptime is critical. They offer guided assessments, automated translation, and customer support that can save weeks of manual work. If you’re technically comfortable and cost-sensitive, open-source tools are excellent: ora2pg remains the most flexible and mature option for schema and logic conversion, while pgloader excels at fast data transfers. Some teams even combine tools—using ora2pg for schema translation and pgloader for bulk data loading—and rely on DBAs to patch the gaps manually.
Full Migration Suites (Commercial). Use it if you require:
- PL/SQL conversion
- Enterprise support
- Zero downtime
- Automated assessments
Examples:
- Oracle-to-PostgreSQL + Code Converter by Intelligent Converters
- AWS Schema Conversion Tool (SCT) if migrating to Amazon RDS/Aurora
Best for: complex schema, enterprise workloads, or limited DBA resources.
Open-Source Tools.Use it if you prefer free tools, have skilled DBAs and you’re comfortable manually fixing conversions.
Examples:
- ora2pg (most popular; robust for schema + data)
- pgloader (high-speed data loader, limited PL/SQL)
Best for: technical teams, standard databases, cost-sensitive migrations.
Hybrid / Custom Pipelines. Some database administrators and developers prefer to bundle migration tools:
- Oracle SQL Developer for export
- ora2pg for schema conversion
- pgloader for data copy
- manual rewriting for PL/SQL
Best for: teams that want maximum control.
Test with a Proof-of-Concept (POC)
Whatever tools you’re considering, do not rely on brochures or reviews. Run a proof of concept. Take a representative slice of your database—a few complicated tables, some procedures, triggers, and large volumes of data—and put each tool through its paces. This will reveal how well the converter handles your real structures, how many errors you can expect, how clear its logs are, and how much manual intervention it demands. The POC also gives you a sense of performance: some tools may take hours for tasks others complete in minutes.
During the POC, validate:
- Schema conversion accuracy
- Data type mapping correctness
- Constraint and identity behavior
- Sequence conversion
- Function/package translation
- Performance (data load speed)
- Logging clarity and debugging ease
Measure:
- Manual fixes needed
- Conversion time
- Error rate
Other Factors to Consider Choosing Migration Tool
As you narrow your choices, pay attention to support, documentation, update frequency, and community activity. A migration tool with poor documentation or slow updates can cause more frustration than it saves. Also factor in the true cost of adoption—not just licensing fees, but DBA time, testing workloads, and the effort needed to rewrite logic the tool cannot translate.
Consider support, documentation, and updates:
- Is support available 24/7?
- Are updates frequent?
- Does the tool maintain active development?
- Are migration guides well written?
- Good support dramatically reduces downtime and frustration.
Calculate total cost including:
- License cost (if commercial)
- DBA time for fixes
- Infrastructure for staging and testing
- Downtime / business impact
- Potential rework or manual rewrites
Often a paid tool is cheaper if manual rewriting is huge.
Recommended Choices Based on Use Case
For a simple or moderate database use ora2pg.
For large enterprise migrations with lots of PL/SQL: Oracle-to-PostgreSQL + Code Converter by Intelligent Converters or AWS SCT (if going to AWS).
For fastest large-scale data loads use pgloader (paired with another schema converter).
For minimal procedural rewrites useEDB Postgres Advanced Server.
Conclusion
In the end, the best Oracle-to-PostgreSQL converter is the one that matches your database’s complexity, your operational constraints, and your team’s expertise. For straightforward migrations, ora2pg is usually enough. For heavy PL/SQL or enterprise-grade migrations, a commercial suite with robust automation might pay for itself many times over. And for teams that like fine-grained control, a hybrid pipeline lets you choose the strongest tool for each phase of the migration.
