Hacktoberfest 2026:メンテナが10月に向けて印を付けた、オープンで初心者向けの issue。 Hacktoberfest の issue を見る

Queueing-time profiler aborts the whole instrumentation install under a JDK 24+ AOT cache (zero spans); disabling that one feature is enough

オープン
#12,540 コメント 5 件 リアクション 0 件 担当者 1 名 GitHub で見る

メンテナーはふだん 2 日以内に返信

@mcculls がすでに取り組んでいます。

2026年9月21日 から。

評価

難易度
4/5
見積もり時間
3〜5日
初心者へのやさしさ
35/100
issue の種類
バグ
明瞭さ
明確に書かれている
活発さ
活発
技術スタック
java
領域
observability

調査の方向性

Start with UnwrappingVisitor and the retransformation path involving RedefinitionStrategy and BatchAllocator. Reproduce with a JDK 25 AOT cache and the queueing-time profiler enabled, then verify that a failed optional transformation no longer aborts installation, spans remain available, and the degradation is logged at info level.

索引モデルが issue の本文から書いたものです。

説明

Tracer Version(s)

1.65.1, 1.66.0

Java Version(s)

25

JVM Vendor

Eclipse Adoptium / Temurin

Bug Report

TL;DR: with a JDK 25 AOT cache, the queueing-time profiler's failed retransformation batch silently aborts the entire instrumentation install (zero spans). Disabling that single feature — -Ddd.profiling.queueing.time.enabled=false — restores all spans and keeps every other profiling capability. Fully disabling the profiler is not necessary.

Behavior

With -XX:AOTCache enabled (jib containerizingMode=packaged, Spring Boot, JDK 25):

  • The tracer starts normally, prints its configuration, reports agent_error: false.
  • Not a single span is produced. No warnings at default log level.
  • Only -Ddd.trace.debug=true reveals: Exception while retransforming 574 classes.

Identical behaviour on 1.65.1 and 1.66.0, so not a recent regression.

Root cause

UnwrappingVisitor (queueing-time profiling) adds the TaskWrapper interface to the classes it instruments. Adding an interface is a structural change, which the JVM rejects on retransformation. Normally this works because the agent installs before those classes load — but a JDK 24+ AOT cache (JEP 483) materializes them before premain.

Since no BatchAllocator is configured, that is the single batch holding every class, and RedefinitionStrategy aborts the whole install. One unusable profiler feature takes all instrumentation down with it.

Why this is filed separately from #10479

#10479 covers partial span loss via the context-store weak-map fallback (addressed by #12105). This is a different mechanism with a total, silent loss — and a much narrower fix surface.

Expected Behavior

A retransformation failure of one optional profiling feature should not abort the entire instrumentation install, and the degradation should be visible at default log level.

Workaround

-Ddd.profiling.queueing.time.enabled=false — all spans return, all other profiling features (CPU, allocation, lock, IO, …) keep working.

The failing setup is exactly the one from the docs, with profiling enabled. Training with the explicit -javaagent:dd-java-agent.jar=aot_training argument fails the same way.

-XX:-AOTClassLinking also avoids it, but gives up the startup gain entirely: on our Spring service startup was 20.5s without a cache, 12.8s with it, and 21.0s with -XX:-AOTClassLinking.

Fix

#12506 retries the failed batch without the interface change. Queueing-time profiling itself keeps working — TaskWrapper is only read by QueueTimeEvent.setTask() and is guarded by instanceof, so the events, durations, scheduler, queue type and span ids are all still recorded; only the task field loses its type resolution (wrapper class instead of the real one). JFR table in #12506. The degradation is logged once at info. With that fix the workaround flag is no longer needed.

Reproduction Code
  1. Spring Boot app, jib containerizingMode=packaged, JDK 25 (Temurin).
  2. Training run: -XX:AOTCacheOutput=app.aot with the agent attached, then run with -XX:AOTCache=app.aot -javaagent:dd-java-agent.jar.
  3. Send requests: zero spans. Add -Ddd.profiling.queueing.time.enabled=false: all spans appear (245 spans in our 20-request measurement, identical to no-AOT baseline — table in #12506).
主要言語
Java
スター
737
フォーク
362
平均マージ
3日 18時間
マージ済み PR(30日)
180

環境構築

はじめの一歩

  1. issue を最後まで読み、次にプロジェクトのコントリビューションガイドを読みます。
  2. 着手することを issue にコメントします — 二人が同じ作業をするのを防げます。
  3. リポジトリをフォークし、ブランチを切って変更します。
  4. issue 番号を参照したプルリクエストを送ります。

DataDog/dd-trace-java のほかの issue

DataDog/dd-trace-java の issue をすべて見る

似ている issue

Java の issue をもっと見る

新しい issue をメールで受け取る

初心者向けの GitHub issue を短くまとめたダイジェスト。