[Feature] Add memory_get_peak_usage to trace information

[TomKeur]

Describe the feature you'd like

We're running our applications in containers on Kubernetes, the memory_limit in PHP's configuration (php.ini) is still set to legacy 1024MB (this is an old value, and has never changed).

Nobody dares to lower it, because we not have any statistics how much memory we're using.

When checking out a Datadog trace (from PHP) I'm seeing:

{
  "php": {
    "compilation": {
      "total_time_ms": 0
    }
  }
}

Maybe it's an idea, to add : memory_get_peak_usage() to this php information, this could be really useful for us.

For example:

{
  "php": {
    "compilation": {
      "total_time_ms": 0
    },
    "memory": {
      "peak_usage_bytes": 1337
    }
  }
}

Also it would be really useful if we're able to add graphs on a Dashboard, with memory usage :).

Is your feature request related to a problem?

It's hard lowering the value of memory_limit because it's not clear how much memory we're using.

Describe alternatives you've considered

Writing these metrics to an OpenMetrics store, so Prometheus can scrape these.

Additional context

No response

[bwoebi]

I have never seen a feature request gaining that many thumbs up in here so quickly :-)

And it's a really easy thing to do - so, here we go, we'll get it with #2840! (in the 1.4.0 release then)