chore(tracing): deprecate DD_TRACE_SPAN_AGGREGATOR_RLOCK

[mabdinur]

DD_TRACE_SPAN_AGGREGATOR_RLOCK configuration exposes tracer implementation details. ddtrace user's should not care about what type of lock is acquired to aggregate span data. This functionality should just work.

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[github-actions]

CODEOWNERS have been resolved as:

releasenotes/notes/deprecate-DD_TRACE_SPAN_AGGREGATOR_RLOCK-eb1ca91f7c1dd2b0.yaml  @DataDog/apm-python
ddtrace/settings/config.py                                              @DataDog/python-guild @DataDog/apm-sdk-api-python
docs/configuration.rst                                                  @DataDog/python-guild
tests/contrib/gunicorn/test_gunicorn.py                                 @DataDog/apm-core-python @DataDog/apm-idm-python

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: munir/deprecate-DD_TRACE_SPAN_AGGREGATOR_RLOCK
Commit report: 1365a55
Test service: dd-trace-py

✅ 0 Failed, 592 Passed, 694 Skipped, 19m 2.06s Total duration (18m 24.06s time saved)

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-09-20 19:49:21

Comparing candidate commit 1365a55 in PR branch munir/deprecate-DD_TRACE_SPAN_AGGREGATOR_RLOCK with baseline commit 33daba9 in branch main.

Found 4 performance improvements and 0 performance regressions! Performance is the same for 352 metrics, 48 unstable metrics.

scenario:iast_aspects-aspect_iast_do_add_and_uppercase

• 🟩 max_rss_usage [-2.629MB; -2.305MB] or [-8.841%; -7.752%]

scenario:iast_aspects-aspect_iast_do_center

• 🟩 max_rss_usage [-2.638MB; -2.350MB] or [-8.860%; -7.893%]

scenario:iast_aspects-aspect_iast_do_index

• 🟩 max_rss_usage [-2.666MB; -2.379MB] or [-8.947%; -7.985%]

scenario:iast_aspects-aspect_iast_do_ljust

• 🟩 max_rss_usage [-2.797MB; -2.489MB] or [-9.385%; -8.353%]

[erikayasuda]

Do we know how many customers actually use this?

[erikayasuda]

nit: Should we keep this for now until we completely remove the env var? Or is it pretty safe to get rid of it preemptively?