This is my current attempt:

import "server-only"
import sql from "mssql"

const sqlConfig: sql.config = {
    user: process.env.DB_USER,
    password: process.env.DB_PASSWORD,
    database: process.env.DB_NAME,
    server: process.env.DB_SERVER!,
    pool: {
        max: 10,
        min: 1,
        idleTimeoutMillis: 30000
    },
    options: {
        encrypt: true,
        trustServerCertificate: true
    }
}

declare global {
    var pool: sql.ConnectionPool | undefined | null;
}

const connectToDatabase = async () => {
    if (!globalThis.pool) {
        globalThis.pool = new sql.ConnectionPool(sqlConfig);
        console.log("Global not found - Created new global ConnectionPool."); // this is never logged
    }

    if (globalThis.pool.connected) {
        return globalThis.pool;
    }

    try {
        await globalThis.pool.connect();
        console.log("Connected to the database."); // this is logged 1x during the whole app lifecycle
        return globalThis.pool;
    } catch (error) {
        console.error("Error connecting to the database:", error); // this is never logged
        globalThis.pool = undefined;
    }
    return null;
};

export default connectToDatabase;

And this is how I use it:

const pool = await connectToDatabase();
const result = await pool!.request().input('employee', session.id).query('my query string')

//use data with result.recordset.... 

This is not going to run on vercel or whatever, the whole app should only run on a single server with nodejs
What i basically need is a connection pool thats available over the whole lifespan of the application, it is kinda working and I get no errors but for some reason during development my ram runs out after ~30 mins and vs code is taking up to 20gb of ram, till i shutdown the dev server. Does not happen on pages not requiring data from the database, so I assume it has something to do with my mssql thing.
This doesn't happen with prisma but I'm not allowed to use any orm like prisma.
Also that's the first time I'm using mssql and the first time not using prisma for my database handling
Any advice on how to solve my problem?