[SOLVED] json requested via Ajax: queries are very fast but response is returned very slowly

Issue

Note this

It’s a single ajax request.

As you can see, I wrote the duration in the result, it’s the duration of all the queries executed in the api backend.

The Response length is 11 KByte, so it’s not a response weight problem.

But as you can see the server is serving the page is 5 seconds.

I’m using nginx, and on this server (it’s a single project dev VPS), there is NO trafic, no concurrency problems.

The backend is made in laravel 8 and it’s doing only this:

    $start = microtime(true);
    $data = $this->articleRepository->getProducts($request->all());
    $duration = microtime(true) - $start;

    return response()->json([
        'status' => 'success',
        'data' => $data,
        'debug' => [
            'duration' => $duration
        ]
    ]);

I tried to replace laravel magics with

    $json = json_encode([
        'status' => 'success',
        'data' => $data,
        'debug' => [
            'duration' => $duration
        ]
    ]);

    return $json;

But it’s taking same time. So I think that is a problem at server side.

By the way, please note that dev VPS is a debian 11 machine in my local network. We already verified that up/down band is well over 350Mbits/secs, symmetric, and stable.

I cannot diagnose it, I have root access to VPS, but I’ve no idea of what could causes so much slowness

Any idea?

Solution

In this very specific case, it was a question of DNS. "localhost" resolution are causing a series of problems and latencies. We moved all pointing from ‘localhost’ to 127.0.0.1 and ALL is resolved.

Note for future Googlers for Laragon and/or Xamp developers: we discovered accidentally that changing localhost to 127.0.0.1 when configuring redis in the laravel .env variabile fixes a huge amount on a windows machine when using both Laragon and Xamp

Answered By – realtebo

Answer Checked By – Marie Seifert (BugsFixing Admin)