What causes "Interrupted during close()" in apache/druid?

Let the interrupt propagate normally — the code restores the flag and continues; verify leftover segments are cleaned by kill tasks

apache/druid · warning

Interrupted during close()

Error message

Interrupted during close()

What it means

StreamAppenderator.close() waits for futures that abandon all persisted segments; if the waiting thread is interrupted, this warning is logged (after restoring the interrupt flag) and close continues to cleanup. Some segments may not have been properly abandoned/dropped.

Solutions

Let the interrupt propagate normally — the code restores the flag and continues; verify leftover segments are cleaned by kill tasks
If leftovers recur, run a kill task for the datasource's unused segments
Avoid interrupting close(); call close on shutdown only after cancel flags are set gracefully
Check logs for the companion 'Unable to abandon existing segments' warning for actual cleanup failures

Defensive patterns

Strategy: try-catch

Try / catch

try {
  appenderator.close();
} catch (RuntimeException e) {
  log.warn(e, "appenderator close interrupted or failed; relying on kill tasks for cleanup");
}

Prevention

Don't interrupt threads that are closing appenderators; use graceful cancel flags first
Schedule periodic kill tasks so partially abandoned segments are cleaned
Alert on 'Interrupted during close()' outside of intentional shutdowns
Allow sufficient shutdown grace period for streaming tasks

When it happens

Trigger: The thread calling StreamAppenderator.close() is interrupted while blocked on Futures.allAsList(futures).get() — e.g. task shutdown interrupting the peon thread, or a supervisor canceling the thread mid-close.

Common situations: Overlord/taskkill issuing interrupts during task shutdown; ingestion task killed while closing its appenderator; timeouts that interrupt cleanup paths.

Related errors

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/ed6fb246a5e327bc. Report an issue: GitHub.

Appendix: source

Thrown at server/src/main/java/org/apache/druid/segment/realtime/appenderator/StreamAppenderator.java:1056

  {
    if (!closed.compareAndSet(false, true)) {
      log.debug("Appenderator already closed, skipping close() call.");
      return;
    }

    log.debug("Shutting down...");

    final List<ListenableFuture<?>> futures = new ArrayList<>();
    for (Map.Entry<SegmentIdWithShardSpec, Sink> entry : sinks.entrySet()) {
      futures.add(abandonSegment(entry.getKey(), entry.getValue(), false));
    }

    try {
      Futures.allAsList(futures).get();
    }
    catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      log.warn(e, "Interrupted during close()");
    }
    catch (ExecutionException e) {
      log.warn(e, "Unable to abandon existing segments during close()");
    }

    try {
      shutdownExecutors();
      Preconditions.checkState(
          persistExecutor == null || persistExecutor.awaitTermination(365, TimeUnit.DAYS),
          "persistExecutor not terminated"
      );
      Preconditions.checkState(
          pushExecutor == null || pushExecutor.awaitTermination(365, TimeUnit.DAYS),
          "pushExecutor not terminated"
      );
      Preconditions.checkState(
          intermediateTempExecutor == null || intermediateTempExecutor.awaitTermination(365, TimeUnit.DAYS),
          "intermediateTempExecutor not terminated"

View on GitHub (pinned to 9b90983fd2)