What causes "Don't query me, bro." in apache/druid?

Query segments via the task's QueryableDruidServer/QueryLifecycle instead of the appenderator directly.

apache/druid · error · IllegalStateException

Don't query me, bro.

Error message

Don't query me, bro.

What it means

StreamAppenderator.getQueryRunnerForIntervals throws IllegalStateException("Don't query me, bro.") when the appenderator's queryRunnerFactoryCollaborator (texasRanger) was never initialized — i.e., the appenderator is not wired into a query infrastructure. The appenderator itself is not queryable until initialized with query support.

Solutions

Query segments via the task's QueryableDruidServer/QueryLifecycle instead of the appenderator directly.
Initialize the appenderator with a QueryRunnerFactoryCollaborator if in-process querying is intended.
Ensure stop() was not called before issuing queries.

Example fix

// before
appenderator.getQueryRunnerForIntervals(query, intervals); // texasRanger null

// after
QueryRunner<T> runner = queryLifecycle.run(query) // or wire collaborator at appenderator construction

Defensive patterns

Strategy: validation

Validate before calling

// only query through the appenderator if it was initialized with query support
if (!appenderatorSupportsQueries(config)) { throw new UnsupportedOperationException("use task query path"); }

Try / catch

try { return runnerFactory.getRunner(...) } catch (IllegalStateException e) { if (e.getMessage().equals("Don't query me, bro.")) { return queryViaTaskApi(query); } throw e; }

Prevention

Never query an Appenderator directly in custom pipelines
Route queries via broker or task's query runner
Don't reuse an appenderator after stop()

When it happens

Trigger: Calling getQueryRunnerForIntervals on an appenderator created without queryRunnerFactoryCollaborator (e.g. BatchAppenderator or tasks that never register a query runner factory), or after stop() clearing the collaborator.

Common situations: Embedding an appenderator in custom ingestion code and attempting to query it directly without registering query runner factories; querying a task's segments through the wrong component.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/5ab456a28ec80e63. Report an issue: GitHub.

Appendix: source

Thrown at server/src/main/java/org/apache/druid/segment/realtime/appenderator/StreamAppenderator.java:546

      try {
        segmentAnnouncer.announceSegment(retVal.getSegment());
      }
      catch (IOException e) {
        log.makeAlert(e, "Failed to announce new segment[%s]", schema.getDataSource())
           .addData("interval", retVal.getInterval())
           .emit();
      }
    }

    return retVal;
  }

  @Override
  public <T> QueryRunner<T> getQueryRunnerForIntervals(final Query<T> query, final Iterable<Interval> intervals)
  {
    if (texasRanger == null) {
      throw new IllegalStateException("Don't query me, bro.");
    }

    return texasRanger.getQueryRunnerForIntervals(query, intervals);
  }

  @Override
  public <T> QueryRunner<T> getQueryRunnerForSegments(final Query<T> query, final Iterable<SegmentDescriptor> specs)
  {
    if (texasRanger == null) {
      throw new IllegalStateException("Don't query me, bro.");
    }

    return texasRanger.getQueryRunnerForSegments(query, specs);
  }

  @Override
  public void clear() throws InterruptedException
  {

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