On Mar 1, 2014, at 3:04 AM, Ni Wesley <nisp...@gmail.com> wrote: > File "/root/workspace/Push Server/server/pymysql/connections.py", line 829, > in _read_bytes > "Lost connection to MySQL server during query (%r)" % (e,)) > OperationalError: (OperationalError) (2013, "Lost connection to MySQL server > during query (error(110, 'Connection timed out'))") 'SELECT > sessions_details.device_token, sessions_details.app_key, > sessions_details.create_time, sessions_details.end_time, > sessions_details.session_status \nFROM sessions_details \nWHERE > sessions_details.app_key = %s AND sessions_details.device_token = %s' > (u'e32c72bab0e4d8e225318f98', u'b8066d12-f34d-4464-bff7-7ff6dcd2e196') > > I don't why this happens, actually, the session blocked for about 5 minutes, > but mysql server works fine at that moment..is 5 minutes special? Or is there > any timeout settings to control session execution timeout? > > Then, I checked the code, and find that, in my whole project, every db > operation use the same global session, is this related? I cannot access the > code now, but raise the question here for discussion. I see some articles on > the net saying, using new created session everytime when db opeation is > required. > > Anybody has such expericenc? should I use new created session every time?
does your program use more than one thread? MySQL connections are not threadsafe and you cannot use a single session (which itself refers to just one connection at a time) across threads (are you sure you’re not using a ScopedSession ?). the issue looks like a deadlock, which would more likely be at the table/row locking level, though I looked up the default timeout for MySQL deadlocks and its 50 seconds (http://dev.mysql.com/doc/refman/5.0/en/innodb-parameters.html#sysvar_innodb_lock_wait_timeout).
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