SystemError: <built-in function utf_8_decode> returned a result with an error set

[Alan Hamlett]

Getting this error when a billiard.exceptions.SoftTimeLimitExceeded exception occurs during a select query:

billiard.exceptions.SoftTimeLimitExceeded:
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/app/myapp/amqp.py", line 161, in decorated
    return fn(*args, **kwargs)
  File "/app/myapp/tasks.py", line 1399, in cache_user_summary
    dt=current,
  File "/app/myapp/utils.py", line 983, in get_summary
    use_cache=use_cache)
  File "/app/myapp/utils.py", line 601, in get_combined_durations
    durations = get_durations(user=user, start=start, end=end, use_cache=use_cache)
  File "/app/myapp/utils.py", line 713, in get_durations
    heartbeats.extend(query.all())
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/orm/query.py", line 2703, in all
    return list(self)
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/orm/loading.py", line 90, in instances
    util.raise_from_cause(err)
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/util/compat.py", line 203, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/util/compat.py", line 187, in reraise
    raise value
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/orm/loading.py", line 67, in instances
    fetch = cursor.fetchmany(query._yield_per)
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/engine/result.py", line 1154, in fetchmany
    self.cursor, self.context)
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1405, in _handle_dbapi_exception
    util.reraise(*exc_info)
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/util/compat.py", line 187, in reraise
    raise value
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/engine/result.py", line 1147, in fetchmany
    l = self.process_rows(self._fetchmany_impl(size))
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/engine/result.py", line 1306, in _fetchmany_impl
    row = self._fetchone_impl()
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/engine/result.py", line 1296, in _fetchone_impl
    self.__buffer_rows()
  File "/app/venv/lib/python3.5/site-packages/sqlalchemy/engine/result.py", line 1283, in __buffer_rows
    self.__rowbuffer = collections.deque(self.cursor.fetchmany(size))
  File "/app/venv/lib/python3.5/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
SystemError: <built-in function utf_8_decode> returned a result with an error set

Using Python 3.5.2, SQLAlchemy 1.1.9 and psycopg2 2.7.1.

[Mike Bayer]

hi there -

do you plan to attach an mcve here? I have no idea what "billiard" is, nor what kind of database you're using, schema, models, any of that, and test cases must be attached with succinct, single-file scripts that have no external dependencies (read the link for more guidelines). As it stands it seems like you have a database with some corrupt unicode data which does not imply any bug in SQLAlchemy.

If you are having general issues debugging a complex program, please get help on the IRC channel or on the mailing list at https://groups.google.com/forum/#!forum/sqlalchemy.

[Alan Hamlett]

I'll get a reproducible testcase. I think it's not related to corrupted data, just related to a long-running query being interrupted when the SoftTimeLimitExceeded is raised from Celery interrupting.

[Mike Bayer]

in any case the stack trace shows the error is within psycopg2 fetchmany(). The method of "interruption" here would be the cause but if it can't be cleanly intercepted by psycopg2, you'd want to report up there.

[Mike Bayer]

please reopen if you have reproducible conditions to add