SQL Server to PostgreSQL Migration Program Playbook

A wave-based program for migrating SQL Server databases to PostgreSQL. It covers complexity assessment, schema and T-SQL conversion with an anti-corruption layer, validated data movement, and a low-downtime cutover.

Difficulty

Advanced

Phases

Total Duration

26 weeks

Roles

Migrating from Microsoft SQL Server to PostgreSQL is a well-trodden path driven by licensing economics and a desire for open, portable infrastructure. PostgreSQL covers the vast majority of SQL Server features, but T-SQL, identity columns, certain data types, and stored-procedure behavior differ enough that conversion needs engineering rigor. This playbook runs the migration as a wave-based program with validation gates.

As with any procedural-code migration, the T-SQL surface (stored procedures, functions, triggers) is where the effort concentrates. Scope it honestly up front.

Phase-by-Phase

Assessment. Inventory databases and consumers, assess T-SQL complexity to size the rewrite, and plan waves so simpler databases build momentum first.

Schema and T-SQL Conversion. Convert schema objects and data types, rewrite T-SQL into PL/pgSQL, and add an anti-corruption layer where applications depend on SQL Server specifics.

Data Movement and Validation. Move data with repeatable pipelines, reconcile record counts and checksums, and validate business-level data quality before cutover.

Cutover. Execute a tested cutover, tune queries against the PostgreSQL optimizer, and decommission SQL Server after a stabilization window.

Team and Roles

A migration architect owns sequencing and target design. DBAs lead schema, conversion, and performance. Data engineers run data pipelines and reconciliation. Backend engineers handle application coupling. QA owns validation and regression.

Risks and Mitigations

T-SQL rewrite effort, data consistency, performance regression, and cutover downtime are the principal risks. Mitigate with complexity scoring, automated reconciliation, load testing before go-live, and CDC-based low-downtime cutover.

Success Criteria

Target verified data parity, query latency at or below the SQL Server baseline, measurable license savings, and zero data loss.

Tooling

Use schema conversion tooling, CDC for synchronization, and PostgreSQL-native observability via Grafana. Run conversion and migration steps through CI for repeatability.

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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SQL Server to PostgreSQL Migration Program Playbook

Phase-by-Phase

Team and Roles

Risks and Mitigations

Success Criteria

Tooling

Category

Tags

See a real scan run