PHOENIX-5215 Migrate from HTrace to OpenTelemetry tracing

[lfrancke]

What changes were proposed in this pull request?

Important

This builds upon #2394 which has stalled for four months now. The four commits from @xavifeds8 are taken as is and later commits build on top of those four.

Removes Apache HTrace from Phoenix and replaces it with a thin OpenTelemetry facade, PhoenixTracing, adapted from HBase's TraceUtil (HBASE-22120).

Per the previous discussions on the mailing list and issue this doesn't depend on an opentelemetry SDK itself and instead relies on the one provided by HBase (2.5+).

HTrace as a direct dependency is banned going forward by maven-enforcer (we still get plenty of transitive ones in the 2.5 profile)

References

• JIRA: PHOENIX-5215
• Supersedes PHOENIX-5215 Migrate from HTrace to OpenTelemetry tracing #2394 (@xavifeds8); earlier attempts PHOENIX-5215 remove SYSTEM.TRACING_STATS related code #1721 (@stoty, draft) and PHOENIX-5215 opentelemetry changes replacing htrace #1282
• Prior art: HBASE-22120
• dev@: [DISCUSS] OpenTelemetry support
• dev@: Remove/replace HTrace (coordination)
• dev@: [DISCUSS] Migrating Phoenix tracing from Htrace to Opentelemetry

Yes, this has been a long time coming :)

Changes on top of #2394

Rebase onto master:

• PhoenixMapReduceUtil.addPhoenixDependencyJars, added to master after PHOENIX-5215 Migrate from HTrace to OpenTelemetry tracing #2394 was written, still shipped htrace-core to YARN containers.
• HTrace is banned going forward by maven-enforcer as direct dependencies only as the HBase 2.5 profile brings in Hadoop 3.2.4 which itself brings in htrace-core4 transitively, not much we can do about that

Correctness:

• Pinned opentelemetry.version to 1.15.0. PHOENIX-5215 Migrate from HTrace to OpenTelemetry tracing #2394 used 1.49.0, but HBase 2.5.3, 2.5.10 and 2.6.1 ship 1.15.0 (2.5.14 and 2.6.3+ ship 1.49.0). Depending on the older version should be safer.
• Stopped storing an OpenTelemetry Scope on PhoenixConnection and TracingIterator. A Scope restores a thread-local and must be closed on the thread that opened it, but a Connection is closed by an arbitrary thread (including the HA framework) and an iterator by whichever thread finishes with it.
• Credited HBase's TraceUtil properly in the PhoenixTracing javadoc, and fixed javadoc placement on the deprecated tracing properties, which sat after @Deprecated and so was not javadoc at all.

Why are the changes needed?

Phoenix's tracing has been non-functional for years, so this removes a dead dependency (with vulnerabilities) and paves the way for a more modern OpenTelemetry pipeline integrated into the stuff HBase provides

Does this PR introduce any user-facing change?

Yes, though only to a feature that was already non-functional anyway (see above).

Removed: writing traces to an HBase table.PhoenixMetricsSink and TraceWriter are gone, so SYSTEM.TRACING_STATS is no longer written. The sink configuration in bin/hadoop-metrics2-phoenix.properties and bin/hadoop-metrics2-hbase.properties is retained but commented out, with a note pointing at the OpenTelemetry agent. SYSTEM.TRACING_STATS itself, the tracing webapp and bin/traceserver.py are untouched, that is the scope of #1721.

Changed: TRACE ON is now inert. The SQL grammar is untouched and the hook remains, so TRACE ON and TRACE OFF still parse and execute without error, but no Phoenix-side trace is started. Previously Phoenix owned a sampler and started its own root traces; under OpenTelemetry, sampling belongs to the SDK and the root span comes from whatever instrumented the caller. I decided to keep this PR to the removal of HTrace and replacing it with OTel. Making TRACE ON useful again can come in a follow-up.

Deprecated: Phoenix tracing properties.phoenix.trace.frequency, phoenix.trace.probability.threshold, phoenix.trace.enabled, phoenix.trace.batchSize, phoenix.trace.threadPoolSize, phoenix.trace.traceBufferSize and phoenix.trace.read.pagesize are marked @Deprecated and no longer read. I'd also be happy to just remove them. Opinions welcome. OpenTelemetry is configured through the agent, for example OTEL_EXPORTER_OTLP_ENDPOINT.

Unchanged: everything else. With no agent attached there is no behaviour change and no overhead.

How was this patch tested?

New PhoenixTracingIT covers the no-op path with no SDK present, TRACE ON / TRACE OFF round-tripping, and that no thread is left pinned to a stale Context after the connection closes.

Locally, against the HBase 2.6 profile:

• Full build green across all 15 modules, including checkstyle, RAT, maven-enforcer and dependency analysis.
• Unit tests green.
• PhoenixTracingIT (3 tests) green
• phoenix-pherf including its integration tests green.
• mvn spotless:check clean across all modules.

Packaging, verified by inspecting the built artifacts.

Was this patch authored or co-authored using generative AI tooling?

Yes. Partially

Generated-by: Claude Opus 5 (Claude Code)

The four commits by @xavifeds8 are preserved unchanged from #2394, no idea about those. The commits above them carry Generated-by: and Co-authored-by: trailers individually, but even those are partially human authored. I've attempted this whole exercise already two or so years ago....and took some of what I had back then.

Per the ASF Generative Tooling Guidance: PhoenixTracing is adapted from HBase's TraceUtil, which is Apache-2.0 and therefore compatible, and this derivation is stated in the class javadoc.

[lfrancke]

Yetus failed twice. The first one was real and I fixed the issues but the second one is no. I believe those test failures are unrelated and seem to happen on master as well.

[Copilot]

Pull request overview

Replaces Phoenix’s obsolete HTrace integration with an OpenTelemetry facade and updates tracing call sites, packaging, configuration, and tests.

Changes:

• Removes HTrace dependencies, sinks, readers, utilities, and tests.
• Adds PhoenixTracing and migrates client/server instrumentation to OpenTelemetry.
• Updates shaded artifacts, runtime configuration, and tracing integration tests.

Reviewed changes

Copilot reviewed 48 out of 50 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/main/config/checkstyle/checker.xml	Changes static-import ordering.
pom.xml	Manages OpenTelemetry and bans HTrace.
phoenix-server/pom.xml	Prevents OpenTelemetry shading.
phoenix-mapreduce-byo-shaded-hbase/pom.xml	Removes HTrace shading exception.
phoenix-core/src/test/java/org/apache/phoenix/trace/TraceSpanReceiverTest.java	Removes receiver tests.
phoenix-core/src/test/java/org/apache/phoenix/metrics/LoggingSink.java	Removes tracing utility dependency.
phoenix-core/src/test/java/org/apache/phoenix/mapreduce/util/PhoenixMapReduceUtilTest.java	Removes HTrace jar assertion.
phoenix-core/src/test/java/org/apache/hadoop/metrics2/lib/ExposedMetricsInfoImpl.java	Removes obsolete test helper.
phoenix-core/src/test/java/org/apache/hadoop/metrics2/impl/ExposedMetricsRecordImpl.java	Removes obsolete test helper.
phoenix-core/src/test/java/org/apache/hadoop/metrics2/impl/ExposedMetricCounterLong.java	Removes obsolete test helper.
phoenix-core/src/it/java/org/apache/phoenix/trace/TracingTestUtil.java	Removes legacy sink helper.
phoenix-core/src/it/java/org/apache/phoenix/trace/PhoenixTracingIT.java	Tests no-SDK and TRACE behavior.
phoenix-core/src/it/java/org/apache/phoenix/trace/PhoenixTracingEndToEndIT.java	Removes legacy tracing ITs.
phoenix-core/src/it/java/org/apache/phoenix/trace/PhoenixTagImpl.java	Removes legacy metrics helper.
phoenix-core/src/it/java/org/apache/phoenix/trace/PhoenixTableMetricsWriterIT.java	Removes table-writer ITs.
phoenix-core/src/it/java/org/apache/phoenix/trace/BaseTracingTestIT.java	Removes HTrace test fixture.
phoenix-core/pom.xml	Replaces test HTrace dependency.
phoenix-core-server/src/main/java/org/apache/phoenix/mapreduce/util/PhoenixMapReduceUtil.java	Stops shipping HTrace jars.
phoenix-core-server/src/main/java/org/apache/phoenix/index/PhoenixTransactionalIndexer.java	Migrates transactional index spans.
phoenix-core-server/src/main/java/org/apache/phoenix/hbase/index/LockManager.java	Migrates row-lock tracing.
phoenix-core-server/src/main/java/org/apache/phoenix/hbase/index/IndexRegionObserver.java	Migrates index observer spans.
phoenix-core-server/src/main/java/org/apache/phoenix/hbase/index/Indexer.java	Migrates indexer spans.
phoenix-core-server/src/main/java/org/apache/phoenix/coprocessor/MetaDataEndpointImpl.java	Removes HTrace initialization.
phoenix-core-server/src/main/java/org/apache/phoenix/coprocessor/BaseScannerRegionObserver.java	Migrates scanner span lifecycle.
phoenix-core-server/pom.xml	Adds provided OpenTelemetry APIs.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/util/Tracing.java	Removes HTrace facade.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/util/NullSpan.java	Removes HTrace no-op span.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/util/ConfigurationAdapter.java	Removes sampler configuration adapter.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/TracingUtils.java	Removes legacy tracing utilities.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/TracingIterator.java	Manages OpenTelemetry iterator spans.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/TraceWriter.java	Removes trace-table writer.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/TraceSpanReceiver.java	Removes HTrace receiver.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/TraceReader.java	Removes trace-table reader.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/PhoenixTracing.java	Adds the OpenTelemetry facade.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/PhoenixMetricsSink.java	Removes legacy metrics sink.
phoenix-core-client/src/main/java/org/apache/phoenix/trace/MetricsInfoImpl.java	Removes tracing metrics helper.
phoenix-core-client/src/main/java/org/apache/phoenix/query/QueryServicesOptions.java	Decouples default frequency from HTrace.
phoenix-core-client/src/main/java/org/apache/phoenix/query/QueryServices.java	Deprecates legacy tracing properties.
phoenix-core-client/src/main/java/org/apache/phoenix/jdbc/PhoenixStatement.java	Traces statement execution with OpenTelemetry.
phoenix-core-client/src/main/java/org/apache/phoenix/jdbc/PhoenixConnection.java	Migrates connection tracing state.
phoenix-core-client/src/main/java/org/apache/phoenix/iterate/SerialIterators.java	Propagates context to serial scans.
phoenix-core-client/src/main/java/org/apache/phoenix/iterate/ParallelIterators.java	Propagates context to parallel scans.
phoenix-core-client/src/main/java/org/apache/phoenix/execute/MutationState.java	Migrates mutation spans.
phoenix-core-client/src/main/java/org/apache/phoenix/execute/BaseQueryPlan.java	Adds query execution spans.
phoenix-core-client/src/main/java/org/apache/phoenix/compile/TraceQueryPlan.java	Adapts TRACE statements to OpenTelemetry.
phoenix-core-client/src/main/antlr3/PhoenixSQL.g	Uses the new TRACE option parser.
phoenix-core-client/pom.xml	Adds provided OpenTelemetry dependencies.
phoenix-client-parent/pom.xml	Prevents client-side OpenTelemetry shading.
bin/hadoop-metrics2-phoenix.properties	Retires Phoenix trace sink configuration.
bin/hadoop-metrics2-hbase.properties	Retires HBase trace sink configuration.

Suppressed comments (1)

phoenix-core-client/src/main/java/org/apache/phoenix/trace/PhoenixTracing.java:214

• If action.get() throws synchronously, the exception escapes without recording the error or ending the newly created span. This leaves a live span that can never be exported. Handle synchronous RuntimeException/Error the same way as exceptional future completion.

 try (Scope ignored = span.makeCurrent()) {
CompletableFuture<T> future = action.get();
endSpan(future, span);
return future;
}

---

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[lfrancke]

Yep, that was my fault. I did not realize that Hadoop 3.2.4 still has HTrace. I've now changed the rule to only look for direct dependencies we add ourselves.

[lfrancke]

Yup, good catch. This should be fixed now.

We didn't use the suggested finally because there is already a finally which runs on every retry iteration. Ending it there would kill the just created span immediately.

[lfrancke]

This was a decision I (human me, not AI) made. I don't know when/how this happened but anyway the existing code fails SpotBugs - maybe the rule was introduced after the code already existed? I don't know. But SpotBugs suggests exactly this pattern as a fix.

I can revert it but then we'll need a SpotBugs exclusion for that line. Personally I think it makes sense to keep this in but I'll let you decide.

[lfrancke]

The docs were wrong, that's true. But other than that this is a port from the HBase version.

Server side this makes no difference as HBase already creates a span, but client side it runs wherever and in those cases it does make sense to start something.

We've chosen to fix the javadoc instead of changing the behavior.

[lfrancke]

@apurtell Thanks for kicking of the review.

I've addressed all comments but can't kick off a re-review myself.
There is one comment where I made a decision that could use another human pair of eyes. I'm fine reverting that as well.