cold-start: split Neon and pg database drivers

[x0ba]

Stack Context

This stack reduces Vercel cold-start time by shrinking the shared SvelteKit server boot path and isolating heavy agent/GitHub dependencies.

Why?

The database module imported both Neon HTTP and pg drivers at startup. Production on Vercel only needs Neon, but still parsed the local Postgres stack on every cold boot.

Test plan

• Confirm Vercel deployment connects to Neon
• Confirm local dev still works against Docker Postgres

[vercel]

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Project	Deployment	Actions	Updated (UTC)
flightlog	Ready	Preview, Comment	May 28, 2026 4:56pm

[x0ba]

• cold-start: tune Sentry sampling and Vercel function limits #45
• cold-start: split Neon and pg database drivers #44 👈 (View in Graphite)
• cold-start: lazy-load agent runner heavy dependencies #43
• cold-start: split regression execution into executor module #42
• cold-start: decouple webhook registration from server hook #41
• staging

This stack of pull requests is managed by Graphite. Learn more about stacking.

[greptile-apps]

Greptile Summary

This PR reduces Vercel cold-start latency by splitting the single database module into two lazily-loaded modules — one for the Neon HTTP driver (production) and one for node-postgres (local Docker). The module entry point uses top-level await import() to load only the relevant driver at runtime, which is valid given the project's ESM configuration ("type": "module").

• index.ts replaces the eager dual-import with a conditional await import() ternary, ensuring only one driver module is parsed and evaluated per cold start.
• local.ts and neon.ts each encapsulate a single driver's initialization logic, keeping the bundle for each environment clean.

Confidence Score: 5/5

Safe to merge — the refactor is a clean mechanical split with no behavioral changes on either the Vercel or local path.

The top-level await import() pattern is valid in this ESM project, the URL routing logic is unchanged, and each new file does exactly what the corresponding branch of the old createDatabase function did. No logic was altered.

No files require special attention.

Important Files Changed

Filename	Overview
src/lib/server/db/index.ts	Refactored to use top-level await import() to lazily load only the needed DB driver; valid ESM pattern given "type": "module" in the project.
src/lib/server/db/local.ts	New file isolating the pg/node-postgres driver; exports an unused LocalDatabase type alias that mirrors AppDatabase.
src/lib/server/db/neon.ts	New file isolating the Neon HTTP driver; retains the pre-existing as unknown as NodePgDatabase cast to satisfy the shared AppDatabase type.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[index.ts module evaluation] --> B{isLocalDatabaseUrl?}
    B -- yes --> C["await import('./local')"]
    B -- no --> D["await import('./neon')"]
    C --> E[createLocalDatabase\npg Pool + drizzle node-postgres]
    D --> F[createNeonDatabase\nneon + drizzle neon-http]
    E --> G[export const db: AppDatabase]
    F --> G

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_{Reviews (2): Last reviewed commit: "Load Neon and pg database drivers throug..." | Re-trigger Greptile}

[x0ba]

Merge activity

• May 28, 4:49 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• May 28, 4:55 PM UTC: Graphite rebased this pull request as part of a merge.
• May 28, 4:56 PM UTC: @x0ba merged this pull request with Graphite.