Drop redundant memory_bytes metrics from ruby_sampler

The following discussion from !30374 (merged) should be addressed:

  • @oswaldo started a discussion: (+7 comments)

    It was here before, but would you know the reason we're setting the same RSS to two different Gauge metrics? 🤔

    Having a look at our metrics catalog, it seems like we just make use of process_resident_memory_bytes. @andrewn would you have some background on that?

It appears that all metrics reporting /proc readings in ruby_sampler.rb report them under the ruby_process_ prefix. However, RSS is currently reported under two different metrics, ruby_process_resident_memory_bytes and ruby_memory_bytes, but they originate from the same system metric.

We should drop ruby_memory_bytes and keep ruby_process_resident_memory_bytes for consistency and reducing confusion.

Tasks:

  • Go through existing dashboards and alerts and ensure that ruby_memory_bytes is unused or update them to use ruby_process_* instead
  • Drop the ruby_memory_bytes gauge

Places where the metric might be referenced:

Edited by Matthias Käppler