Support using GlobalObjectStore for non-field-injected contexts by mcculls · Pull Request #12381 · DataDog/dd-trace-java

mcculls · 2026-09-02T11:26:43Z

What Does This Do

Adds a feature-flag to support switching non-field-injected InstrumentationContext from using a WeakMap per-store to instead use the shared GlobalObjectStore from dd-instrument-java.

The default value of this feature-flag is true, in other words the historical behaviour of using a map-per-store:

To switch to GlobalObjectStore set the following environment variable:

DD_TRACE_RUNTIME_CONTEXT_MAP_PER_STORE=false

or add this JVM option:

-Ddd.trace.runtime.context.map-per-store=false

Motivation

The GlobalObjectStore approach scales better for deployments using a lot of non-field-injected instrumentation context where periodic cleanup / GC cannot keep up. For example on AOT where we cannot field-inject classes linked at training time. See #10479 for more details.

GlobalObjectStore uses a generational approach to evict old content, keeping the store bounded while still allowing tracking of recent instrumentation contexts. Whereas the map-per-store approach immediately drops new content if the store reaches capacity, and this causes async propagation issues on AOT until GC finally kicks in.

Since the generational strategy is relatively new, the idea is to roll this out incrementally as we complete further benchmarking of various real-world applications.

Contributor Checklist

Format the title according to the contribution guidelines
Assign the type: and (comp: or inst:) labels in addition to any other useful labels
Avoid using close, fix, or any linking keywords when referencing an issue
Use solves instead, and assign the PR milestone to the issue
Update the CODEOWNERS file on source file addition, migration, or deletion
Update public documentation with any new configuration flags or behaviors
Once approved, use merge queue to merge the PR

Jira ticket: [PROJ-IDENT]

dd-octo-sts · 2026-09-02T11:50:23Z

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	14.79 s	14.66 s	[-0.1%; +1.9%] (no difference)
startup:insecure-bank:tracing:Agent	13.59 s	13.68 s	[-1.4%; -0.0%] (maybe better)
startup:petclinic:appsec:Agent	17.51 s	16.72 s	[+0.5%; +9.0%] (maybe worse)
startup:petclinic:iast:Agent	17.25 s	17.52 s	[-2.4%; -0.7%] (maybe better)
startup:petclinic:profiling:Agent	17.40 s	17.13 s	[+0.1%; +3.1%] (maybe worse)
startup:petclinic:sca:Agent	17.06 s	17.43 s	[-6.4%; +2.2%] (no difference)
startup:petclinic:tracing:Agent	16.53 s	16.22 s	[-2.5%; +6.3%] (no difference)

Commit: edd9ecf2 · CI Pipeline · Benchmarking Platform UI

Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.

mcculls · 2026-09-03T15:50:57Z

@DataDog review

Copilot

🔵 Needs a closer look

It modifies core runtime context storage and bytecode-injected fallback behavior, so it warrants a final human review to validate bootstrap/classloader safety and rollout risk.

Pull request overview

This PR adds a new configuration flag to control how non-field-injected InstrumentationContext storage behaves, allowing a rollout from the historical “weak map per store” fallback to the bounded, shared GlobalObjectStore implementation (from dd-instrument-java) for better scalability in scenarios like AOT class linking.

Changes:

Introduces trace.runtime.context.map-per-store (env: DD_TRACE_RUNTIME_CONTEXT_MAP_PER_STORE, default true) and wires it into InstrumenterConfig.
Switches non-field-injected context storage in FieldBackedContextStore (and injected accessor fallbacks) between WeakMapPerStore and GlobalObjectStore based on the new flag.
Refactors ContextStore factory APIs to use java.util.function.Function rather than a custom KeyAwareFactory.

File summaries

File	Description
metadata/supported-configurations.json	Registers the new env var flag in supported configuration metadata.
internal-api/src/main/java/datadog/trace/bootstrap/ContextStore.java	Replaces custom key-aware factory type with `Function` and adapts `Factory` accordingly.
internal-api/src/main/java/datadog/trace/api/InstrumenterConfig.java	Loads and exposes the new `runtimeContextMapPerStore` flag.
dd-trace-api/src/main/java/datadog/trace/api/ConfigDefaults.java	Adds the default value constant for the new flag.
dd-trace-api/src/main/java/datadog/trace/api/config/TraceInstrumentationConfig.java	Defines the canonical config key `trace.runtime.context.map-per-store`.
dd-java-agent/instrumentation/reactive-streams-1.0/src/test/java/datadog/trace/instrumentation/reactivestreams/ReactiveStreamsContextPropagationTest.java	Updates a test `ContextStore` implementation to the new `Function`-based API.
dd-java-agent/instrumentation/graal/graal-native-image-20.0/src/main/java/datadog/trace/instrumentation/graal/nativeimage/NativeImageGeneratorRunnerInstrumentation.java	Adds `GlobalObjectStore` classes to Graal native-image init-at-build-time list.
dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/context/FieldBackedContextInjector.java	Selects the injected fallback redirect class (`WeakMapPerStore` vs `GlobalObjectStore`) based on the new flag.
dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/utils/StrongMapContextStore.java	Updates the store implementation to accept `Function` factories.
dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/WeakMapPerStore.java	Updates weak fallback store compute path to use `Function.apply`.
dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/FieldBackedContextStore.java	Switches non-field-injected storage between `WeakMapPerStore` and `GlobalObjectStore` under the feature flag.

Review details

Files reviewed: 11/11 changed files
Comments generated: 0
Review effort level: Lite

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datadog-official

This change removes KeyAwareFactory and changes the ContextStore#getOrCompute method descriptor. Existing runtime extensions that use this API can fail to load.

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mcculls added type: feature Enhancements and improvements tag: do not merge Do not merge changes comp: core Tracer core labels Sep 2, 2026

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mcculls force-pushed the mcculls/global-object-store-feature branch 5 times, most recently from 286fa56 to c7a0fb4 Compare September 3, 2026 11:47

Replace KeyAwareFactory with standard Function type

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mcculls force-pushed the mcculls/global-object-store-feature branch from de73d43 to ec23bdd Compare September 3, 2026 15:13

mcculls changed the title ~~WIP: Support using GlobalObjectStore for non-field-injected contexts~~ Support using GlobalObjectStore for non-field-injected contexts Sep 3, 2026

mcculls removed the tag: do not merge Do not merge changes label Sep 3, 2026

mcculls requested a lite review from Copilot September 3, 2026 15:50

Copilot started reviewing on behalf of mcculls September 3, 2026 15:51 View session

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Comment thread internal-api/src/main/java/datadog/trace/bootstrap/ContextStore.java

mcculls marked this pull request as ready for review September 3, 2026 16:18

mcculls requested review from a team as code owners September 3, 2026 16:18

mcculls requested review from mhlidd and sarahchen6 and removed request for a team September 3, 2026 16:18

mcculls requested a review from ValentinZakharov September 3, 2026 16:18

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Comment thread internal-api/src/main/java/datadog/trace/bootstrap/ContextStore.java

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mhlidd approved these changes Sep 3, 2026

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mcculls added 2 commits September 3, 2026 18:01

Support using GlobalObjectStore for non-field-injected contexts

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Remove leftover reference to KeyAwareFactory

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mcculls force-pushed the mcculls/global-object-store-feature branch from 9369ab2 to edd9ecf Compare September 3, 2026 17:05

sarahchen6 approved these changes Sep 3, 2026

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mcculls requested a review from daniel-mohedano September 3, 2026 18:16

mcculls enabled auto-merge September 3, 2026 20:20

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Support using GlobalObjectStore for non-field-injected contexts - #12381

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