随机错误"在查询期间与MySQL服务器的连接丢失"与Django 1.3

Question

这个线程没有太大帮助:在查询期间丢失了与MySQL服务器的连接.

我将max_allowed_pa​​cket增加到16M,max_connections增加到9999.但是,我仍然收到此错误:

  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 107, in _result_iter
    self._fill_cache()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 772, in _fill_cache
    self._result_cache.append(self._iter.next())
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 273, in iterator
    for row in compiler.results_iter():
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 680, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 735, in execute_sql
    cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 86, in execute
    return self.cursor.execute(query, args)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.6-intel.egg/MySQLdb/cursors.py", line 174, in execute
    self.errorhandler(self, exc, value)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/MySQL_python-1.2.3-py2.7-macosx-10.6-intel.egg/MySQLdb/connections.py", line 36, in defaulterrorhandler
    raise errorclass, errorvalue
OperationalError: (2013, 'Lost connection to MySQL server during query')

它有点随机发生,任何人都可以对它有所了解吗？

Answer 1

一些可能性(部分来自https://serverfault.com/questions/29597/what-does-mysql-error-2013-mean/30036#30036):

• 由于负载条件,查询花费的时间比正常时间长(因此是随机的),并且超出服务器的wait_timeout(不太可能)或net_wait_timeout(可能).
• 您正在使用sql代理,该代理在完成之前就会终止连接.
• 您与mysql服务器的网络连接是不稳定的.尝试ping它一段时间,看看你是否有丢包.

另一种可能性是由于缺少索引,庞大的数据集或您正在使用的表引擎(可能是InnoDB或MyISAM)的限制,查询本身非常昂贵.确定这个问题的一个好方法是找到导致问题的QuerySet,从QuerySet获取原始sql(请参阅从Django QuerySet获取SQL),然后在您选择的mysql shell中运行带有EXPLAIN的查询.