SQL Lab. Celery task.forget() is not supported by all backends. "NotImplementedError: backend does not implement forget."

[jinhyukchang]

Hi,
We are using SQS on Celery and with this PR, it invokes forget() call, but it seems SQS backend has not implemented it. From Google search, AMQP also hasn't implemented it yet.

Since, not all backend implementation has this method implemented, how about isolate this failure by wrapping with try...except?

Traceback (most recent call last):
  File "/srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/superset/views/core.py", line 2117, in _sql_json_async
    task.forget()
  File "/srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/celery/result.py", line 146, in forget
    self.backend.forget(self.id)
  File "/srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/celery/backends/base.py", line 463, in forget
    self._forget(task_id)
  File "/srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/celery/backends/base.py", line 466, in _forget
    raise NotImplementedError('backend does not implement forget.')
NotImplementedError: backend does not implement forget.

Expected results

No exception when user submit query from SQL Lab.

Actual results

Failing with message at https://github.com/apache/incubator-superset/blob/master/superset/views/core.py#L2142

Screenshots

If applicable, add screenshots to help explain your problem.

How to reproduce the bug

1. Use SQS as Celery backend
2. Submit query in SQLLab

Environment

(please complete the following information):

• superset version: 0.37
• python version: 3.6

Checklist

Make sure these boxes are checked before submitting your issue - thank you!

• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

Add any other context about the problem here.

[issue-label-bot]

Issue-Label Bot is automatically applying the label #bug to this issue, with a confidence of 0.66. Please mark this comment with 👍 or 👎 to give our bot feedback!

Links: app homepage, dashboard and code for this bot.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. For admin, please label this issue .pinned to prevent stale bot from closing the issue.

[willbarrett]

Closing as fixed.