chore: update span buffer and min flush count

[juanjux]

increase DD_TRACE_WRITER_BUFFER_SIZE_BYTES to 30MB and decrease DD_TRACE_PARTIAL_FLUSH_MIN_SPANS to 200 spans.

Also update the documentation, which actually had a wrong value.

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/update-span-buffer-sizes-18552a87bf54f8ef.yaml       @DataDog/apm-python
ddtrace/internal/constants.py                                           @DataDog/apm-core-python
ddtrace/settings/_config.py                                             @DataDog/apm-core-python
docs/configuration.rst                                                  @DataDog/python-guild
tests/integration/test_integration.py                                   @DataDog/apm-core-python

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 277 ± 2 ms.

The average import time from base is: 281 ± 5 ms.

The import time difference between this PR and base is: -4.6 ± 0.2 ms.

Import time breakdown

The following import paths have shrunk:

ddtrace.auto 2.236 ms (0.81%)

ddtrace.bootstrap.sitecustomize 1.546 ms (0.56%)

ddtrace.bootstrap.preload 1.546 ms (0.56%)

ddtrace.internal.remoteconfig.client 0.710 ms (0.26%)

ddtrace 0.690 ms (0.25%)

ddtrace.internal._unpatched 0.033 ms (0.01%)

json 0.033 ms (0.01%)

json.decoder 0.033 ms (0.01%)

re 0.033 ms (0.01%)

enum 0.033 ms (0.01%)

types 0.033 ms (0.01%)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-06-30 14:11:41

Comparing candidate commit 57a0e21 in PR branch juanjux/update-traces-default-sizes with baseline commit 563f14b in branch main.

Found 0 performance improvements and 1 performance regressions! Performance is the same for 530 metrics, 3 unstable metrics.

scenario:iastaspects-format_map_aspect

• 🟥 execution_time [+441.714ns; +524.346ns] or [+13.667%; +16.223%]

[emmettbutler]

Why?