分布式爬虫时出现异常：redis.exceptions.ResponseError:DISCARDwithoutMULTI

Traceback (most recent call last):

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/commands/crawl.py", line 58, in run

    self.crawler_process.start()

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/crawler.py", line 291, in start

    reactor.run(installSignalHandlers=False)  # blocking call

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/twisted/internet/base.py", line 1267, in run

    self.mainLoop()

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/twisted/internet/base.py", line 1276, in mainLoop

    self.runUntilCurrent()

--- ---

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/twisted/internet/base.py", line 902, in runUntilCurrent

    call.func(*call.args, **call.kw)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/utils/reactor.py", line 41, in __call__

    return self._func(*self._a, **self._kw)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/core/engine.py", line 122, in _next_request

    if not self._next_request_from_scheduler(spider):

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy/core/engine.py", line 149, in _next_request_from_scheduler

    request = slot.scheduler.next_request()

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy_redis_bloomfilter/scheduler.py", line 175, in next_request

    request = self.queue.pop(block_pop_timeout)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/scrapy_redis/queue.py", line 115, in pop

    results, count = pipe.execute()

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/redis/client.py", line 3443, in execute

    return execute(conn, stack, raise_on_error)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/redis/client.py", line 3339, in _execute_transaction

    self.immediate_execute_command('DISCARD')

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/redis/client.py", line 3275, in immediate_execute_command

    return self.parse_response(conn, command_name, **options)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/redis/client.py", line 3402, in parse_response

    self, connection, command_name, **options)

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/redis/client.py", line 768, in parse_response

    respOnse= connection.read_response()

  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/redis/connection.py", line 638, in read_response

    raise response

redis.exceptions.ResponseError: DISCARD without MULTI