vendor lock-in → exit plan
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Databases migration path

From Oracle Database to PostgreSQL

Cost comparison, a phase-by-phase migration plan, and the automation to execute it.

Effort
High
Est. timeline
~18 wks
PostgreSQL model
Free (optional support)
Open source
Yes
▶ Model your savings in the calculator

3-year cost calculator

Pre-filled for Oracle Database → PostgreSQL. Adjust every figure with your own numbers.

Every figure here is an illustrative estimate, not a vendor quote. Defaults are editable starting points compiled from public information; real, binding pricing comes from the vendor or an authorized distributor. See our methodology.

Sized at 64 vCPUs — cost is computed on this.
Stay on Oracle Database (3yr)
$326,400
Move to PostgreSQL (3yr + migration)
$79,680
Projected savings
$246,720 (76%)
Payback period
8.1 mo
Build a decision report from these numbers:

How this is licensed: Oracle and SQL Server license by the vCPUs of the database server VM. Oracle applies a per-core factor and counts ALL vCPUs unless the workload runs on approved hard-partitioned or Oracle-engineered hardware; SQL Server has a 4-vCPU-per-VM minimum. Set $/vCPU to your edition and core factor.

All figures are illustrative and fully editable — adjust the cost-per-vCPU and migration inputs with your own numbers. Not guaranteed vendor pricing (defaults reviewed May 2026). For a binding quote, use the request form below to reach an authorized distributor or partner.

Quick comparison: Oracle Database vs PostgreSQL

Common trade-offs teams weigh when staying on Oracle Database versus moving to PostgreSQL. These are general, commonly-reported considerations — not statements of fact about any vendor — so check them against your own contract and the vendors' current terms.

Oracle Database Current
Oracle · Per-core perpetual + support
  • Already in production — no migration effort or risk
  • Mature ecosystem with vendor support and SLAs
  • Per-core licensing widely regarded as among the most expensive
  • Reported audit activity and licensing-compliance exposure
  • Hard-partitioning policy can limit virtualization savings
  • Steep annual support renewal uplifts are commonly reported
  • Ongoing per-core perpetual + support cost to budget for
  • Higher vendor lock-in to weigh
PostgreSQL Planned
Open source · Free (optional support)
  • Open source — no license fees
  • No vendor lock-in
  • Cost model: Free (optional support)
  • Requires a migration (~18 weeks, high effort)
  • Community support by default — paid support optional
  • Higher operational learning curve

In-depth guide

Oracle Database is among the most capable — and most expensive — pieces of software in the enterprise. Per-core licensing, mandatory support uplifts, hard-partitioning rules that limit virtualization savings, and the ever-present risk of an audit make it a perennial target for cost reduction. PostgreSQL is the most common open-source destination: a mature, standards-leaning relational database with strong SQL support, extensions for almost everything, and no license fee. But “no license fee” is not the same as “free migration.” Here’s the realistic picture.

The economics

Oracle’s cost is driven by the vCPUs of the database server. Oracle applies a core factor and, critically, expects you to license all the cores a workload could run on — so virtualizing Oracle on a shared cluster often means licensing the whole cluster unless you use approved hard partitioning or Oracle-engineered systems. PostgreSQL removes the license entirely; your ongoing cost becomes infrastructure plus optional commercial support (EDB, Percona, Crunchy Data, etc.). For most workloads the three-year TCO drops sharply — the question is migration effort, not whether it saves money.

What ora2pg automates — and what it doesn’t

ora2pg is the workhorse. It connects to Oracle, assesses migration complexity and estimates effort, exports schema (tables, indexes, constraints, sequences), converts much of your PL/SQL to PL/pgSQL, and migrates data in parallel. Start with the assessment report:

ora2pg -t SHOW_REPORT --estimate_cost -c ora2pg.conf > assessment.txt

It will not magically convert everything. The parts that need human attention:

  • PL/SQL packages and complex procedures. Simple logic converts cleanly; packages, autonomous transactions, and heavy use of Oracle built-ins need rework.
  • Datatype and semantics differences. NUMBER without precision, DATE (which carries time in Oracle), empty-string-equals-NULL behavior, and sequence/ROWNUM patterns all need review.
  • Oracle-specific features. RAC, partitioning syntax, materialized-view refresh semantics, hierarchical CONNECT BY, and certain analytic functions map differently (or to extensions).
  • Application SQL. Hints, (+) outer joins, DUAL, and PL/SQL called from the app must be updated. This is often the largest hidden cost.

A defensible migration flow

  1. Assess with ora2pg; triage objects by conversion difficulty.
  2. Provision the target — a primary plus replicas, sized on vCPU, with backups and parameter tuning.
  3. Convert schema, review the action items, and load it into PostgreSQL.
  4. Migrate data — a bulk load for the cutover rehearsal, then change-data-capture (CDC) replication to keep the target current with low downtime.
  5. Convert procedures and application SQL; this proceeds in parallel with data work.
  6. Validate with row counts, checksums/data-diffs, an application regression suite, and query-plan/performance comparisons against the Oracle baseline.
  7. Cut over during a window: stop writes (or set Oracle read-only), let CDC drain to zero lag, run a final diff, repoint connection strings, smoke-test, and keep Oracle recoverable through hypercare.

Keeping T-SQL-style compatibility (the SQL Server cousin)

If you’re migrating SQL Server rather than Oracle and the application rewrite is the blocker, Babelfish for Aurora PostgreSQL can accept T-SQL/TDS directly, dramatically reducing app changes. There’s no equivalent for Oracle’s PL/SQL, but EDB Postgres Advanced Server offers a high degree of Oracle compatibility if you want to minimize conversion effort at the cost of a commercial subscription.

Testing is the project

The single biggest predictor of a smooth Oracle→PostgreSQL cutover is the depth of the parallel-run and validation phase. Run both databases in parallel, replay representative workloads, compare results and query plans, and only promote when the target meets documented acceptance criteria (correctness, performance, and failover). Budget real time here — it’s cheaper than discovering a behavioral difference in production.

Bottom line

Oracle→PostgreSQL reliably lowers licensing cost; the work is schema/PL-SQL conversion, application SQL changes, and rigorous validation — not the data movement itself. ora2pg handles the mechanical 70–90%; plan engineering time for the rest, run CDC to minimize downtime, and validate exhaustively before cutover. Use the calculator above to model your vCPU-based savings, and treat the figures as illustrative until a distributor or support vendor quotes your environment.

Why teams evaluate alternatives to Oracle Database

Reasons commonly cited by users and in public industry coverage for re-evaluating Oracle Database. These are general, reported considerations — not statements of fact about Oracle — and may not reflect your situation or the vendor's current terms. Verify against your own contract before deciding.

  • Per-core licensing widely regarded as among the most expensive
  • Reported audit activity and licensing-compliance exposure
  • Hard-partitioning policy can limit virtualization savings
  • Steep annual support renewal uplifts are commonly reported

The migration plan

Roughly 18 weeks for a mid-size estate, in six phases.

Assessment & discovery
Inventory every workload, dependency, and integration; flag anything high-risk.
Target design & sizing
Size the new platform, design storage and networking, set RPO/RTO and rollback criteria.
Pilot migration
Migrate a small low-risk set end-to-end and validate the runbook.
↳ ora2pg for schema and data; convert PL/SQL to PL/pgSQL; validate with a parallel run.
Production migration
Move workloads in scheduled waves using automation; verify after each wave.
Validation & optimization
Tune performance, confirm backup/DR, and update monitoring and docs.
Decommission source
Reclaim licenses, retire old infrastructure, and capture lessons learned.

Tooling & automation

ora2pg for schema and data; convert PL/SQL to PL/pgSQL; validate with a parallel run.

OffVendor's wizard pre-fills these scripts with your environment — inventory export, disk/schema conversion, bulk provisioning, and validation.

Frequently asked

Is migrating from Oracle Database to PostgreSQL worth it?

For most teams facing rising Oracle Database costs, yes — PostgreSQL (free (optional support)) typically lowers 3-year total cost of ownership, though the right answer depends on workload complexity and in-house skills. Use the calculator to model your own numbers.

How long does a Oracle Database to PostgreSQL migration take?

A typical mid-size estimate is around 18 weeks across six phases — discovery, design, pilot, waved production migration, validation, and decommission. Larger or more complex estates take longer.

What tools are used to migrate from Oracle Database to PostgreSQL?

ora2pg for schema and data; convert PL/SQL to PL/pgSQL; validate with a parallel run.

Get a vendor-accurate PostgreSQL quote

A guided builder that turns your estimates into a requirements report you can send to a vendor, partner, or distributor to secure a binding quote.

How this works — and what's yours to provide
  • Your inputs, your responsibility. The figures and estimates here describe your environment and requirements — please make sure they're accurate. OffVendor's defaults are illustrative starting points only, not vendor pricing.
  • It generates a requirements report (RFQ). Use it to capture your sizing and requirements and share it with your authorized vendor / partner / distributor to obtain a final, binding quote.
  • Then close the loop on your TCO. When the real quote comes back, plug those actual prices into the calculator above to refine your TCO and see where reality differs from the estimate.
  1. 1Size it
  2. 2Requirements
  3. 3Your details
  4. 4Channels & export

How big is your Oracle Database estate?

Count the OS/database server VMs and their typical vCPU allocation. Licensing usually counts all vCPUs on each VM. Not sure? Enter rough numbers — the distributor confirms exact counts later.

64 vCPUs
Default mid-size assumption (64 vCPUs)
Estimates are illustrative and configurable; production figures come from vendor list prices and your own quotes.