public void requestFailed(Throwable reason) throws PrestoException { // cancellation is not a failure if (reason instanceof CancellationException) { return; } if (reason instanceof RejectedExecutionException) { throw new PrestoException(REMOTE_TASK_ERROR, reason); } // log failure message if (isExpectedError(reason)) { // don't print a stack for a known errors log.warn("Error " + jobDescription + " %s: %s: %s", taskId, reason.getMessage(), taskUri); } else { log.warn(reason, "Error " + jobDescription + " %s: %s", taskId, taskUri); } // remember the first 10 errors if (errorsSinceLastSuccess.size() < 10) { errorsSinceLastSuccess.add(reason); } // fail the task, if we have more than X failures in a row and more than Y seconds have passed // since the last request if (backoff.failure()) { // it is weird to mark the task failed locally and then cancel the remote task, but there is // no way to tell a remote task that it is failed PrestoException exception = new PrestoException( TOO_MANY_REQUESTS_FAILED, format( "%s (%s %s - %s failures, time since last success %s)", WORKER_NODE_ERROR, jobDescription, taskUri, backoff.getFailureCount(), backoff.getTimeSinceLastSuccess().convertTo(SECONDS))); errorsSinceLastSuccess.forEach(exception::addSuppressed); throw exception; } }