I think this might be an integration mismatch between Prisma’s MariaDB adapter and how attachDatabasePool() detects supported pool objects.

From what I can see, @prisma/adapter-mariadb is designed to receive a connection string or config, not an already-created pool instance. So instead of passing a pool, I’d try initializing it like this:

1import { PrismaMariaDb } from '@prisma/adapter-mariadb'2import { PrismaClient } from 'generated/prisma/client'34const adapter = new PrismaMariaDb(process.env.DATABASE_URL!)56export const prisma = new PrismaClient({ adapter })

The Unsupported database pool type error seems to come from attachDatabasePool(pool), which suggests it may not recognize the shape of the MariaDB pool being used here.

My guess is that Prisma itself is working fine, but attachDatabasePool() might not currently support this specific Prisma + MariaDB adapter setup (or expects a different pool format).

Might be worth confirming with Vercel whether this combination is officially supported

Switching to mysql2 is a practical solution here, since attachDatabasePool is compatible with that driver and works correctly with Fluid Compute