Thank you, Mike! I would have never extracted your interpretation from the trace! (I don’t know the code…)
The two questions that arise now, though, are - Why would connections drop out of the pool, is this a configuration problem that I should worry about? - The request still failed with a 502 although, as you said, it’s a harmless exception. What is the proper way of handling these situations? Still learning new things here, and I’m curious about your suggestions :-) Jens On Friday, September 29, 2017 at 6:59:48 AM UTC+10, Mike Bayer wrote: > > On Thu, Sep 28, 2017 at 2:48 PM, <jens.t...@gmail.com <javascript:>> > wrote: > > Hello, > > > > I’m using SQLAlchemy (1.1.13) and SQLAlchemy-Utils (0.32.14) in the > context > > of a Pyramid (1.9.1) web-browser, PyMySQL (0.7.11) as a driver, and > mysql > > 5.6.3. I followed the Pyramid/Alchemy Cookiecutter implementation. > > > > On seemingly random requests (although all seem to be OPTIONS) I see the > > following exception in the server logs (see also this PyMySQL issue): > > > > 2017-09-28 18:13:17,765 ERROR > > [sqlalchemy.pool.QueuePool][b'uWSGIWorker1Core0'] Exception during reset > or > > similar > > Traceback (most recent call last): > > File > "/var/www/…/lib64/python3.6/site-packages/sqlalchemy/engine/base.py", > > line 1182, in _execute_context > > context) > > File > > "/var/www/…/lib64/python3.6/site-packages/sqlalchemy/engine/default.py", > > line 470, in do_execute > > cursor.execute(statement, parameters) > > File "/var/www/…/lib64/python3.6/site-packages/pymysql/cursors.py", > line > > 166, in execute > > result = self._query(query) > > File "/var/www/…/lib64/python3.6/site-packages/pymysql/cursors.py", > line > > 322, in _query > > conn.query(q) > > File > "/var/www/…/lib64/python3.6/site-packages/pymysql/connections.py", > > line 856, in query > > self._affected_rows = self._read_query_result(unbuffered=unbuffered) > > File > "/var/www/…/lib64/python3.6/site-packages/pymysql/connections.py", > > line 1057, in _read_query_result > > result.read() > > File > "/var/www/…/lib64/python3.6/site-packages/pymysql/connections.py", > > line 1340, in read > > first_packet = self.connection._read_packet() > > File > "/var/www/…/lib64/python3.6/site-packages/pymysql/connections.py", > > line 1001, in _read_packet > > % (packet_number, self._next_seq_id)) > > pymysql.err.InternalError: Packet sequence number wrong - got 102 > expected 8 > > > > > > I see this error in different variations for the packet sequence. Any > hint > > or tip to explain this issue is appreciated! > > the log seems to indicate the connection pool has gotten the > connection back and is attempting to emit a rollback() upon it. These > can fail if the connection has already had some varieties of error > occur upon it, most often when the work on the connection was > interrupted, such as when receiving a greenlet or thread exit. It's > likely when a WSGI request is interrupted, the cleanup logic here > fails because the connection has been thrown into an invalid state. > The connection is invalidated (e.g. discarded) in this case and is > harmless. > > > > > > Thank you! > > Jens > > > > -- > > SQLAlchemy - > > The Python SQL Toolkit and Object Relational Mapper > > > > http://www.sqlalchemy.org/ > > > > To post example code, please provide an MCVE: Minimal, Complete, and > > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > > description. > > --- > > You received this message because you are subscribed to the Google > Groups > > "sqlalchemy" group. > > To unsubscribe from this group and stop receiving emails from it, send > an > > email to sqlalchemy+...@googlegroups.com <javascript:>. > > To post to this group, send email to sqlal...@googlegroups.com > <javascript:>. > > Visit this group at https://groups.google.com/group/sqlalchemy. > > For more options, visit https://groups.google.com/d/optout. > -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
