Broken Pipe Error

[postelrich]

I have a Python 3.4 program running and about after 8-10 hours, it starts throwing the below exception.  The best I found by searching was to set wait_timeout in my.cnf to a higher value but that hasn't worked.  I'm connecting with pymysql using autocommit.  Any clue on what causes this exception and how to handle it?

Traceback (most recent call last):

  File "/home/ntx/.ntx_path/platform/ntx/common/db.py", line 211, in _executemany

    self.cursor.executemany(statement, params)

  File "/home/ntx/ntx-py3/lib/python3.4/site-packages/pymysql/cursors.py", line 157, in executemany

    self.rowcount = sum(self.execute(query, arg) for arg in args)

  File "/home/ntx/ntx-py3/lib/python3.4/site-packages/pymysql/cursors.py", line 157, in <genexpr>

    self.rowcount = sum(self.execute(query, arg) for arg in args)

  File "/home/ntx/ntx-py3/lib/python3.4/site-packages/pymysql/cursors.py", line 135, in execute

    result = self._query(query)

  File "/home/ntx/ntx-py3/lib/python3.4/site-packages/pymysql/cursors.py", line 274, in _query

    conn.query(q)

  File "/home/ntx/ntx-py3/lib/python3.4/site-packages/pymysql/connections.py", line 713, in query

    self._execute_command(COM_QUERY, sql)

  File "/home/ntx/ntx-py3/lib/python3.4/site-packages/pymysql/connections.py", line 892, in _execute_command

    self._write_bytes(prelude + sql[:chunk_size-1])

  File "/home/ntx/ntx-py3/lib/python3.4/site-packages/pymysql/connections.py", line 852, in _write_bytes

    raise OperationalError(2006, "MySQL server has gone away (%r)" % (e,))

pymysql.err.OperationalError: (2006, "MySQL server has gone away (BrokenPipeError(32, 'Broken pipe'))")

[Naoki INADA]

Did you set wait_timeout on server, and restert it?

You can confirm your setting is applied correctly with following query.

mysql> select @@wait_timeout;

mysql> select @@global.wait_timeout;

To avoid this error, you can connect and close each time.

Or use connection pool like SQLAlchemy's engine.

[Tushar Niras]

Yes I'm agree with Naoki. The best practice is open and close connection each time and kepp closed when you're not using.