if you're storing sessions in the database an update is made for every
request that changes the session ..... can you confirm that this would be
the case (i.e. your app does a lot of session.whatever changes) ?
On Tuesday, April 16, 2013 11:09:50 PM UTC+2, Yarin wrote:
>
> We've had our production application running problem free for 10 months,
> but in the past month or so we've started encountering "MySQL server has
> gone away" errors sporadically, but with increasing frequency. Currently it
> is happening every few days, sometimes several times a day. This has never
> happened to the app in test or development environments.
>
> These factors lead me to believe this problem is manifesting itself as a
> result of increased activity. Still, our loads are relatively low. We may
> have a handful of users connected at any one time, but not more than 10.
>
> Looking at our Newrelic database reports, we're seeing that the a huge
> spike in db clock time always coincides with the errors, and the culprit is
> always the *web2py_session_* UPDATE call. (It may possibly correlated
> with new user signups, but we haven't been able to confirm this)
>
> Stranger still, in one of these incidents there were over a hundred calls
> made to web2py_session_{app} UPDATE, many times the number of total
> requests made to the app over the same period.
>
> Traces:
>
> Traceback (most recent call last):
> File "/opt/web-apps/web2py/gluon/main.py", line 624, in wsgibase
> BaseAdapter.close_all_instances('rollback')
> File "/opt/web-apps/web2py/gluon/dal.py", line 529, in close_all_instances
> db._adapter.close(action)
> File "/opt/web-apps/web2py/gluon/dal.py", line 509, in close
> getattr(self, action)()
> File "/opt/web-apps/web2py/gluon/dal.py", line 1655, in rollback
> if self.connection: return self.connection.rollback()
> File
> "/usr/lib/python2.6/site-packages/newrelic-1.12.0.9/newrelic/hooks/database_dbapi2.py",
> line 76, in rollback
> return self._nr_connection.rollback()
> OperationalError: (2006, 'MySQL server has gone away')
>
>
> and
>
> Traceback (most recent call last):
> File "/opt/web-apps/web2py/gluon/main.py", line 551, in wsgibase
> session._try_store_in_db(request, response)
> File "/opt/web-apps/web2py/gluon/globals.py", line 726, in _try_store_in_db
> table._db(table.id == record_id).update(**dd)
> File "/opt/web-apps/web2py/gluon/dal.py", line 8812, in update
> ret = db._adapter.update(tablename,self.query,fields)
> File "/opt/web-apps/web2py/gluon/dal.py", line 1372, in update
> self.execute(sql)
> File "/opt/web-apps/web2py/gluon/dal.py", line 1694, in execute
> return self.log_execute(*a, **b)
> File "/opt/web-apps/web2py/gluon/dal.py", line 1688, in log_execute
> ret = self.cursor.execute(*a, **b)
> File
> "/usr/lib/python2.6/site-packages/newrelic-1.12.0.9/newrelic/hooks/database_dbapi2.py",
> line 36, in execute
> return self._nr_cursor.execute(sql, *args, **kwargs)
> File "/usr/lib64/python2.6/site-packages/MySQLdb/cursors.py", line 173, in
> execute
> self.errorhandler(self, exc, value)
> File "/usr/lib64/python2.6/site-packages/MySQLdb/connections.py", line 36,
> in defaulterrorhandler
> raise errorclass, errorvalue
> OperationalError: (1205, 'Lock wait timeout exceeded; try restarting
> transaction')
>
>
>
> What could be the cause of all this? Any ideas welcome.
>
>
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