Sdk attribute limits

[jack-berg]

Alternative to #8656 that removes all limits-related public API surface area from opentelemetry-sdk, putting it in opentelemetry-sdk-common instead.

The goal of this whole effort was to try to unify on a single attributes implementation (ArrayBackedAttributesBuilder,
ArrayBackedAttributes) which backs the default Attributes implementation from the public API.

But after a lot of experimenting I think this is a dead end:

• The additional limits enforcement / dropped attribute counting requires a substantial amount of additional work / coordination such that maintaining a common abstraction in ArrayBackedAttributesBuilder, ArrayBackedAttributes is actually more work than maintaining two separate implementations.
• The array based attribute implementation is a real impediment to performance compared to a HashMap based implementation. Even with attempts at optimization, I think we're still looking at a 5-30% performance hit in span / log recording by trying to standardize on the array based implementation. Hard to stomach.

I'm opening this PR as just as a record to look back on in case we ever start thinking in this direction again. I will close it right away and think we should go for a version of #8656 instead.

[otelbot]

⚠️ API changes detected — additional maintainer review required

@jack-berg @jkwatson

This PR modifies the public API surface area of the following module(s):

• opentelemetry-sdk-common

Please review the changes in docs/apidiffs/current_vs_latest/ carefully before approving.

[opentelemetry-pr-dashboard]

Pull request dashboard status

Closed · refreshed 2026-07-31 19:34 UTC

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[codecov]

Codecov Report

❌ Patch coverage is 80.26756% with 59 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.43%. Comparing base (bc956bc) to head (237706f).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...io/opentelemetry/sdk/common/LimitedAttributes.java	74.20%	38 Missing and 19 partials ⚠️
.../main/java/io/opentelemetry/sdk/trace/SdkSpan.java	88.23%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8681      +/-   ##
============================================
- Coverage     91.47%   91.43%   -0.04%     
- Complexity    10465    10511      +46     
============================================
  Files          1021     1022       +1     
  Lines         27694    27810     +116     
  Branches       3247     3276      +29     
============================================
+ Hits          25333    25428      +95     
- Misses         1617     1630      +13     
- Partials        744      752       +8     

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