SQL Server to PostgreSQL Migration Blueprint

A migration plan from Microsoft SQL Server to PostgreSQL covering T-SQL-to-PL/pgSQL conversion, type mapping, collation handling, and DMS-based CDC cutover.

From

SQL Server

PostgreSQL

Difficulty

Advanced

Duration

20 weeks

Team Size

medium

Overview

Microsoft SQL Server is a strong commercial RDBMS, but its per-core licensing is costly and it ties teams to the Microsoft stack. PostgreSQL offers comparable features under an open-source license. This blueprint migrates schema, T-SQL logic, and data while keeping application behavior identical.

The key challenges are T-SQL stored procedures, identity columns, MERGE statements, and SQL Server quirks such as case-insensitive default collations and the [bracket] identifier syntax.

Phases

Assessment. Inventory databases, stored procedures, functions, triggers, and SQL Agent jobs. Use AWS SCT or sqlserver2pgsql to estimate conversion effort and flag unsupported constructs.

Schema conversion. Map types: NVARCHAR to varchar/text, DATETIME2 to timestamp, BIT to boolean, MONEY to numeric. Replace IDENTITY with GENERATED AS IDENTITY. Decide collation strategy, since PostgreSQL is case-sensitive by default.

Code migration. Rewrite T-SQL procedures as PL/pgSQL. Convert ISNULL to COALESCE, GETDATE() to now(), TOP n to LIMIT n, and MERGE to INSERT ... ON CONFLICT. Port SQL Agent jobs to pg_cron or external schedulers.

Data migration. Bulk-extract with bcp and load via COPY, or use AWS DMS for ongoing replication. For minimal downtime, run DMS CDC so the target tracks source changes.

Cutover. Reconcile row counts and checksums, run read-only validation, then switch the connection strings during a planned window.

Key Risks and Mitigations

Data consistency: Validate counts and checksums; keep CDC deltas small before cutover.
T-SQL incompatibility: MERGE, table-valued parameters, and CROSS APPLY need rewrites. Triage and convert iteratively.
Downtime: Use AWS DMS CDC for near-zero-downtime switchover.

Recommended Tooling

AWS SCT and AWS DMS for automated conversion and replication; sqlserver2pgsql for schema translation; bcp for extraction; pg_stat_statements for tuning.

Success Metrics

License-cost reduction, query latency parity, zero data-integrity defects, and stable post-cutover error rates.

Prerequisites

Object inventory, collation decision, performance baselines on SQL Server, and a tested rollback path.

See a real scan run

A replay of the actual CLI running against our test repositories — live progress, real findings, a genuine DriftScore. Nothing executes in your browser.

Replay

demo@vibgrate — bash

❯ npx @vibgrate/cli scan

╭──────────────────────────────────────────╮

│ Vibgrate Drift Report │

╰──────────────────────────────────────────╯

── node-turborepo (node) .

Runtime: >=18.0.0 (6 majors behind)

Frameworks:

Turbo: 1.13.4 → 2.10.12 (1 behind)

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Dependencies:

1 current 1 1-behind 3 2+ behind 1 unknown

── @repo/admin (node) apps/admin

Frameworks:

TanStack Query: 5.102.5 → 5.102.5 (current)

React: 18.3.1 → 19.2.8 (1 behind)

React DOM: 18.3.1 → 19.2.8 (1 behind)

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Vite: 5.4.21 → 8.2.2 (3 behind)

Dependencies:

3 current 9 1-behind 3 2+ behind 4 unknown

── @repo/api (node) apps/api

Frameworks:

Express: 4.22.2 → 5.2.1 (1 behind)

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Vitest: 1.6.1 → 4.1.11 (3 behind)

Dependencies:

7 current 5 1-behind 3 2+ behind 4 unknown

── @repo/web (node) apps/web

Frameworks:

Next.js: 14.2.35 → 16.3.3 (2 behind)

React: 18.3.1 → 19.2.8 (1 behind)

React DOM: 18.3.1 → 19.2.8 (1 behind)

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Dependencies:

2 current 6 1-behind 3 2+ behind 5 unknown

── @repo/config (node) packages/config

Frameworks:

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Dependencies:

2 current 2 1-behind 5 2+ behind 0 unknown

── @repo/database (node) packages/database

Frameworks:

Prisma: 5.22.0 → 7.10.0 (2 behind)

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Dependencies:

1 current 0 1-behind 3 2+ behind 1 unknown

── @repo/types (node) packages/types

Frameworks:

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Dependencies:

0 current 0 1-behind 1 2+ behind 1 unknown

── @repo/ui (node) packages/ui

Frameworks:

React: 18.3.1 → 19.2.8 (1 behind)

TypeScript: 5.9.3 → 7.0.2 (2 behind)

React: 18.3.1 → 19.2.8 (1 behind)

Dependencies:

1 current 4 1-behind 1 2+ behind 1 unknown

── @repo/utils (node) packages/utils

Frameworks:

TypeScript: 5.9.3 → 7.0.2 (2 behind)

Vitest: 1.6.1 → 4.1.11 (3 behind)

Dependencies:

0 current 1 1-behind 2 2+ behind 1 unknown

Tech Stack

Frontend: React, React DOM

Meta-frameworks: Next.js

Bundlers: tsx, Turbo, Vite

CSS / UI: Autoprefixer, PostCSS, Tailwind CSS

Backend: Express

ORM / Database: Prisma, Prisma Client

Testing: Vitest

Lint & Format: ESLint, ESLint Prettier, ESLint React, Prettier, typescript-eslint

Services & Integrations

Auth: JWT 9.0.3

Databases: Prisma 5.22.0

TypeScript

v5.3.3 · strict ✔ · MIXED · target: ES2022

Build & Deploy

Package Managers: pnpm

Monorepo: npm-workspaces, pnpm-workspaces, turbo

Product Purpose Signals

Frameworks: react, nextjs

Evidence: 177

Top Signals:

- [heading] Dashboard (apps/admin/src/pages/Dashboard.tsx)

- [title] Revenue Overview (apps/admin/src/pages/Dashboard.tsx)

- [copy] workspace:* (packages/ui/package.json)

- [copy] ./dist (packages/ui/tsconfig.json)

- [copy] ./src/index.ts (packages/ui/package.json)

- [copy] @repo/config/tsconfig-base.json (packages/ui/tsconfig.json)

- [copy] @repo/ui (packages/ui/package.json)

- [copy] #3b82f6 (apps/admin/src/pages/Dashboard.tsx)

Unknowns:

- No pricing or billing evidence found.

- No integrations/connectors evidence found.

- No route structure evidence found.

Security Posture

Lockfile ✖ · .env ✔ · node_modules ✔

Platform

Native modules: turbo

Code Quality

Files: 36 · Functions: 183 · Avg complexity: 2.62 · Avg length: 21.13 lines

Max nesting: 2 · Circular deps: 0 · Dead code: 0%

God files: apps/admin/src/pages/Products (448 lines)

Database Schema

postgresql · 8 models · 1 enum

Models: Address, CartItem, Category, Order, OrderItem (+3 more)

Findings (16 errors, 11 warnings)

✖ Node.js runtime ">=18.0.0" reached end-of-life on 2025-04-30 (latest: 24.0.0).

vibgrate/runtime-eol in .

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in .

✖ 60% of dependencies are 2+ major versions behind in node-turborepo.

vibgrate/dependency-rot in .

✖ @types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).

vibgrate/dependency-major-lag in .

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in apps/admin

✖ Vite is 3 major versions behind (current: 5.4.21, latest: 8.2.2).

vibgrate/framework-major-lag in apps/admin

✖ vite is 3 major versions behind (spec: ^5.0.12, latest: 8.2.2).

vibgrate/dependency-major-lag in apps/admin

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in apps/api

✖ Vitest is 3 major versions behind (current: 1.6.1, latest: 4.1.11).

vibgrate/framework-major-lag in apps/api

✖ @types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).

vibgrate/dependency-major-lag in apps/api

✖ vitest is 3 major versions behind (spec: ^1.2.1, latest: 4.1.11).

vibgrate/dependency-major-lag in apps/api

⚠ Next.js is 2 major versions behind (current: 14.2.35, latest: 16.3.3).

vibgrate/framework-major-lag in apps/web

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in apps/web

✖ @types/node is 6 major versions behind (spec: ^20.11.0, latest: 26.3.0).

vibgrate/dependency-major-lag in apps/web

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in packages/config

✖ 56% of dependencies are 2+ major versions behind in @repo/config.

vibgrate/dependency-rot in packages/config

✖ eslint-plugin-react-hooks is 3 major versions behind (spec: ^4.6.0, latest: 7.1.1).

vibgrate/dependency-major-lag in packages/config

⚠ Prisma is 2 major versions behind (current: 5.22.0, latest: 7.10.0).

vibgrate/framework-major-lag in packages/database

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in packages/database

✖ 75% of dependencies are 2+ major versions behind in @repo/database.

vibgrate/dependency-rot in packages/database

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in packages/types

✖ 100% of dependencies are 2+ major versions behind in @repo/types.

vibgrate/dependency-rot in packages/types

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in packages/ui

⚠ TypeScript is 2 major versions behind (current: 5.9.3, latest: 7.0.2).

vibgrate/framework-major-lag in packages/utils

✖ Vitest is 3 major versions behind (current: 1.6.1, latest: 4.1.11).

vibgrate/framework-major-lag in packages/utils

✖ 67% of dependencies are 2+ major versions behind in @repo/utils.

vibgrate/dependency-rot in packages/utils

✖ vitest is 3 major versions behind (spec: ^1.2.1, latest: 4.1.11).

vibgrate/dependency-major-lag in packages/utils

╭──────────────────────────────────────────╮

│ Top Priority Actions │

╰──────────────────────────────────────────╯

1. Upgrade EOL runtime in node-turborepo

End-of-life runtimes no longer receive security patches and block ecosystem upgrades.

./.

>=18.0.0 → 24.0.0 (6 majors behind)

Impact: −10 drift points (runtime & EOL)

2. Fix security posture: no lockfile found

Without a lockfile, installs are non-deterministic. Run the install command to generate one and commit it.

Missing: package-lock.json, pnpm-lock.yaml, or yarn.lock

3. Upgrade Vite 5.4.21 → 8.2.2 in @repo/admin (+2 more)

3 major versions behind. Major framework drift increases breaking change risk and blocks access to security fixes and performance improvements.

./apps/admin

Vite: 5.4.21 → 8.2.2 (3 majors behind)

./apps/api

Vitest: 1.6.1 → 4.1.11 (3 majors behind)

./packages/utils

Vitest: 1.6.1 → 4.1.11 (3 majors behind)

Impact: −5–15 drift points

4. Reduce dependency rot in @repo/types (100% severely outdated)

1 of 1 dependencies are 2+ majors behind. Run `npm outdated` and prioritise packages with known CVEs or breaking API changes.

./packages/types

typescript: 5.9.3 → 7.0.2 (2 majors behind)

Impact: −5–10 drift points

5. Reduce dependency rot in @repo/database (75% severely outdated)

3 of 4 dependencies are 2+ majors behind. Run `npm outdated` and prioritise packages with known CVEs or breaking API changes.

./packages/database

@prisma/client: 5.22.0 → 7.10.0 (2 majors behind)

prisma: 5.22.0 → 7.10.0 (2 majors behind)

typescript: 5.9.3 → 7.0.2 (2 majors behind)

Impact: −5–10 drift points

╭──────────────────────────────────────────╮

│ Architecture Layers │

╰──────────────────────────────────────────╯

Archetype: nextjs (80% confidence)

Files classified: 24 (11 unclassified)

Folders classified: 8

apps/admin/src presentation 100% 4 files

apps/admin/src/pages presentation 100% 2 files

apps/api/src/middleware middleware 100% 2 files

apps/api/src/routes routing 100% 2 files

apps/web/src/app presentation 100% 4 files

apps/web/src/app/products presentation 100% 2 files

apps/web/src/app/products/[id] presentation 100% 1 file

packages/ui/src presentation 100% 6 files

Unclassified source (sample): 11

presentation 15 files drift ████████████████████ 100 risk high

routing 4 files drift ████████████████████ 100 risk high

middleware 2 files drift ███████▍░░░░░░░░░░░░ 37 risk moderate

config 2 files drift ░░░░░░░░░░░░░░░░░░░░ 0 risk none

shared 1 file drift ████████████████████ 100 risk high

╭──────────────────────────────────────────╮

│ DriftScore Summary │

╰──────────────────────────────────────────╯

DriftScore: 66/100

Risk Level: HIGH

Projects: 9

Classified: 8 nano · 1 micro · 0 small · 0 standard

Billable: 0.42 · 9 detected → 0.42 billable projects (micro-project pricing)

0.1 micro · 0.32 nano

These fractions add up across repositories, then round down to whole billable projects.

Score Breakdown

Runtime: ████████████████████ 100

Frameworks: █████████▏░░░░░░░░░░ 46

Dependencies: ██████▏░░░░░░░░░░░░░ 31

EOL Risk: ████████████████████ 100

Scanned at 2026-08-26T09:08:28.481Z · 7.1s · 286 files scanned · 56 workspace files · 27 dirs

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Explore the Vibgrate CLI

SQL Server to PostgreSQL Migration Blueprint

Overview

Phases

Key Risks and Mitigations

Recommended Tooling

Success Metrics

Prerequisites

Tags

See a real scan run