Cache prometheusize rename between scrapes

[vigno88]

After profiling the exporter because it had a somewhat high cpu usage, it reported that the regexp operations in this function accounts for more than 10% of the cpu time.

More precisely, the first call to prometheusize uses 3.79%, the second 5.86% (in exporter.MakeMetrics) and lastly it 1.03% (in exporter.MakeRawMetrics)

This all goes to zero if we cache them.

[it-percona-cla]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 3 committers have signed the CLA.

:white_check_mark: vigno88
:white_check_mark: idoqo
:x: vigno99
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[vigno88]

pprof.mongodb_exporter.samples.cpu.pb.gz

[idoqo]

Hi @vigno88 looks like tests are still failing - also looks like the profile you shared was from before the change - will be nice to have both to see how they compare.

[vigno88]

Hi, thanks for the quick response.

I'll take a look at the tests and yes i will provide a new profile.

Nathan AV

[BupycHuk]

Hi, please also make sure that it's thread-safe.

[vigno88]

i've signed the CLA a lot of time last week and I tried again today. It says that the signature was made, but the status of the issue doesn't update..

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 65.50%. Comparing base (dc46ed5) to head (24099d3). Report is 104 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1080      +/-   ##
==========================================
- Coverage   70.88%   65.50%   -5.39%     
==========================================
  Files          28       29       +1     
  Lines        3569     3073     -496     
==========================================
- Hits         2530     2013     -517     
- Misses        904      922      +18     
- Partials      135      138       +3     

Flag	Coverage Δ
agent	65.50% <100.00%> (-5.39%)	:arrow_down:

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[vigno88]

There are other changes is this profile, but this show the cpu usage of prometheusize after the changes. https://flamegraph.com/share/a322d13f-2f3a-11f0-8b23-2a8f4480f552

[vigno88]

All the test have passed, and the signature for my account has passed (vigno99 is the user of my computer)

[idoqo]

Thanks a lot for your contribution, @vigno88. I'll check with our internal QA team about testing this, and then we can merge.

[idoqo]

Hi @vigno88 , ready to merge this now, but seems there were also some commits from @vigno99 , so the CLA needs to be signed by both accounts

[vigno88]

vigno99 looks like an autogenerated git user on my work computer. It's not linked to any github account.. I can't log to anything with it