A weird issue: speed dropped

[lnlife]

Here is my code:

import express from "express";
import postgres from "postgres";
const sql = postgres('postgres://test:test@127.0.0.1:5432/test')
const port = 3000;
const app = express();

app.get("/", async (req, res) => {
    for (let i = 1; i <= 20; i++) {
        const xs = await sql`select * from posts where id=1`
    }
    res.send(`ok`);
});
app.listen(port, () => {
    console.log(`Listening on port ${port}...`);
});

I run the following ab test: ab -n 2000 -c 5 http://localhost:3000 ( number:2000, concurrency: 5 requests at a time) The result is stable at around 900/sec, whatever times repeat the command.

Then I run: ab -n 2000 -c 10 http://localhost:3000 (change 5 to 10) The result is still around 900/sec

Then issue came. When I run ab -n 2000 -c 5 http://localhost:3000 (change 10 back to 5) After repeat this command several times, the results significantly dropped to 150/sec, and even keep dropping. If I restart the express server, and run the above command, it become stable at 900/sec again. This issue is that, if I set -c 10 and then set -c 5, the reqeusts/sec will drop significantly.

I have tested both ts-node and bun, both express and bun native serve, same issue occured.

[WIGGLES-dev]

Can confirm experiencing same issue in bun, performance degrades between stress test. Notably the issue is only present when max connections is set great than 1. So it may be a pooling issue.

[porsager]

This is a very nice repro @lnlife ! Thank you! I've looked closer, and there's a really bad regression all the way back from 3.0.1. I'll be looking deeper into this tomorrow.

[divmgl]

Is this still happening? I was about to go all in on postgres for some of the services in our codebase given the sheer amount of performance problems with Prisma.

[lnlife]

Is this still happening? I was about to go all in on postgres for some of the services in our codebase given the sheer amount of performance problems with Prisma.

Yes it is. I have to set {max:1} in the connection option to stop pool. Even so, it is still the fasted client.

[jonataslaw]

any update on this?