Ora2Pg vs HexaRocket: From the Creator of Ora2Pg

If you’ve migrated databases from Oracle to PostgreSQL, you’re likely familiar with Ora2Pg. I am Gilles Darold, the creator of Ora2Pg. As the CTO of HexaCluster, I’m also actively working on HexaRocket - an enterprise database migration tool designed to simplify production-grade migrations. Many customers ask us about the differences between Ora2Pg and HexaRocket. That’s why I’m writing this article on Ora2Pg vs HexaRocket, to share where Ora2Pg continues to shine in modern Database Migration, where teams typically need additional support at scale, and how HexaRocket builds on those lessons.

If you have used Ora2Pg on a large-scale migration program, you’ll recognize a common reality, i.e., Database Migration is rarely “just” moving tables and data - no matter which tool you start with. The real work often sits in code conversion, validation, cutover planning, and making the process repeatable when you’re coordinating multiple teams and applications. HexaRocket supports a deterministic code conversion engine and validation at every stage, an advanced UI, online data migration with live replication, and rollback support using multiple CDC techniques - ultimately making migrations faster, more predictable, and easier to operate.

Ora2Pg, two decades of Database Migration Reality

I started the Ora2Pg project in 2001. Since then, it has been maintained continuously, shaped by real-world migrations, and hardened by countless edge cases. Over more than two decades, Ora2Pg has likely supported tens of thousands and possibly far more of Oracle to PostgreSQL migration journeys (directly or indirectly). Many consulting vendors have built Database Migration services around Ora2Pg, because it’s practical, transparent, and flexible.

I have also watched Ora2Pg become a foundation layer inside other tooling. Some cloud services and service providers silently integrated it under the hood because it worked, and it was free.

What open source taught me (and why HexaRocket exists)

When you maintain a free tool like Ora2Pg, you see a pattern: many organizations depend on it in Database Migration work, they file issues and request enhancements, and they rarely contribute improvements back. Especially when those improvements become part of their commercial service offerings.

I always tried to do my part - implement features, fix corner cases, and keep Ora2Pg moving forward. But sustaining a tool at that level, while the industry keeps demanding “more automation,” “more online,” “more validation,” “less risk” eventually becomes a bigger mission than volunteer time allows.

That’s also where my collaboration with Avi began in a deeper way. Avi Vallarapu is the CEO of HexaCluster, and when I joined HexaCluster, as a CTO, and previously MigOps, we spent a lot of time discussing what the future of Database Migration should look like.

We had great ideas, and some of them made it into Ora2Pg itself such as integrating oracle_fdw, adding row count and full data validation, CDC readiness by capturing table start SCNs, and some more practical enhancements that came from doing difficult migrations repeatedly.

But we also realized something else: simplifying migrations even further requires investment - engineering time, product design, support, and a roadmap that can move faster than volunteer time allows.

So, we built HexaRocket with some more capabilities.

Ora2Pg vs HexaRocket - what problem are we really solving?

The comparison isn’t “good vs better.” It’s about scope and operational intent.

Ora2Pg is excellent when you want a powerful command-line approach, flexible configuration, and offline Database Migration execution that you can script, version-control, and run in repeatable ways.

HexaRocket is built for end-to-end migrations, including online migrations, UI-driven observability, and accelerating complex code conversion with an advanced code conversion engine, home trained LLM plus other LLM integration, and deterministic validation layers.

Yes, LLMs can help… and yes, they can hallucinate

Around July 2023, we asked ourselves a question. Can we significantly improve conversion success rates beyond the current state of the art? The obvious candidate was AI Code Conversion using LLMs. But LLMs can hallucinate - confidently producing output that looks correct but breaks semantics or fails validation.

So, we didn’t treat the Code Conversion as “ask a model, accept output.” We designed a system where LLMs are guided, constrained, validated, and when needed - overruled.

Training a domain specific model to reduce hallucinations

We started training our own model called: HexaCluster Language Model (HeLM) focused narrowly on Oracle PL/SQL to PostgreSQL PL/pgSQL, SQL Server T-SQL to PostgreSQL, and the SQL patterns that matter in real Database Migration. We intentionally avoided broad general-purpose text. In AI Code Conversion, creativity is a bug.

For about eight months, we generated and curated training samples, human-generated, covering a wide range of Oracle syntax and conversion patterns. By early 2024, we had a model that demonstrated better instruction handling and more stable conversion output.

Deterministic conversions are the real secret sauce behind HexaRocket

We wish it was as easy as asking an LLM to convert Oracle PL/SQL to PostgreSQL PL/pgSQL. It’s not. HexaRocket code conversion engines also LLMs at some point, but it also relies on multiple layers of deterministic engineering such as parsing and segmentation, guided transformations with a complex rule system, validations against syntax and known semantics, and feedback loops that keep conversions consistent.

Customer choice of LLM

Enterprises are beginning to certify LLM providers and constrain usage to approved environments. HexaRocket was designed to support customer choice of LLM. If a customer wants to use a trusted external model rather than deploying ours, HexaRocket can integrate those models into the same guided pipeline, still using our deterministic parsing, validators, and conversion constraints.

Now, comes the question: What is Ora2Pg good for?

Ora2Pg remains a strong choice when you want a command-line schema conversion and data migration tool, you are comfortable with configuration-driven control, you are doing offline Database Migration, and your code conversion needs are moderate (or you have manual conversion capacity).

When HexaRocket is the better fit?

Teams choose HexaRocket when they need an end-to-end Database Migration platform for Production database migrations with UI-driven workflows that remove operational complexity, transparent progress tracking, higher-speed conversion of complex code objects with LLM integration guided by an advanced code conversion engine with deterministic validation, and a path beyond offline into online migration strategies.

HexaRocket vs Ora2Pg feature comparison table

Feature	HexaRocket	Ora2Pg
Primary Use Case	End-to-end Database Migration (schema conversion + validation + data migration + CDC + rollback options)	Schema conversion + offline data export/import
User Interface (UI)	Web UI; centralized view of schema, data, CDC, and code objects	Command-line tool with config files
Status & Progress	Object-level states (Pending/In Progress/Completed/Failed/Manual) with real-time visibility	Status inferred from console output and log files
Logs & Observability	Structured, searchable logs in UI; stage-wise and object-wise context	Flat files / console logs; manual triage
Retry / Resume	Retry failed objects individually; resume from checkpoints; safe retries	Manual reruns; often requires rework and careful handling
Reports	One-click downloadable reports (schema, data, validation, CDC)	Manual reporting
Object-level Control	Selective migration by schema/table/object type; enable/disable objects	Config-driven inclusion/exclusion; manual sequencing
Schema Conversion Depth	Supports basic + complex data types; strong support for partitions, indexes, constraints (with broader coverage)	Good for most of the data types/tables; with some limitations
Code Conversion Approach	Workflow-driven engine with many rules + Code Conversion engine + validation	Regex-based keyword replacement rules
Code Conversion Accuracy	Targeting >95% for many workloads (with validation and guided conversion)	Moderate for basic objects; low for complex objects
LLM Support	HexaCluster-trained model + option to integrate customer-approved LLMs	No LLM integration
Validation	Converted code validation; online/offline data validation; resynchronization workflows	Limited validation – currently restricted to offline validation; requires manual steps.
CDC (Replication)	Log-based CDC + batch-based CDC; pause/resume; lag dashboards; per-table controls	No CDC
Rollback	Rollback and reverse replication options for safer cutovers (where applicable)	No rollback
Performance & Tuning	Parallelism and performance controls exposed via UI; table-level tuning	Parallel export/import available but requires manual tuning and manual procedures
Enterprise Readiness	Secure credential handling, RBAC, regulated environment support; on-prem/cloud/isolated	Security handled externally; configs often require careful handling

HexaRocket - supports database migration between more databases

Following are the list of supported Source and Target database engines for enterprise database migration using HexaRocket.

Source Database	Target Database	Schema Migration	Data Migration	CDC
Oracle	PostgreSQL	✔️	✔️	✔️
SQL Server (MSSQL)	PostgreSQL	✔️	✔️	✔️
PostgreSQL	Oracle	✔️	✔️	✔️
PostgreSQL	SQL Server (MSSQL)	✔️	✔️	✔️
Oracle	Oracle	✔️	✔️	✔️
PostgreSQL	PostgreSQL	✔️	✔️	✔️
MySQL	PostgreSQL	✔️	✔️	✔️
MariaDB	PostgreSQL	✔️	✔️	✔️
Oracle	MariaDB	✔️	✔️	✔️

Closing thoughts

Ora2Pg helped the world migrate, and it continues to do so. But the next stage of Database Migration, i.e., online migration, enterprise validation, guided automation, and production-grade code conversion requires sustained investment and a platform built to carry that weight. That platform is HexaRocket.

If you need expert support migrating legacy or complex Oracle, SQL Server, MySQL, or MariaDB databases to PostgreSQL or distributed databases, we’re here to help.

HexaCluster provides end-to-end migration and modernization services, including application migration and modernization, database migration, and PostgreSQL consulting such as performance tuning, health audits, managed DBA services, and 24/7/365 support.

To start a conversation or explore how we can support your migration journey, please contact us at connect@hexacluster.ai

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