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POsqlalchemy + mysql deadlocks
 

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  1. POsqlalchemy + mysql deadlocks
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    <p>I insert rows with random data into mysql database. After inserting some rows, greenlet hangs on connecting. Statistics printing greenlet keeps running</p> <p>This happens with any number of workers (including one), both with mysql-connector and mysqldb drivers. sqlite works fine.</p> <p><a href="http://groups.google.com/group/gevent/browse_thread/thread/e77df0ceb9cbd05b/b7422f27daae4344" rel="nofollow">This</a> has no effect (as i understand it is already fixed in new gevent)</p> <pre><code>def patch(): from gevent import monkey monkey.patch_all() # fix https://bugs.launchpad.net/myconnpy/+bug/712037 from mysql.connector.connection import MySQLConnection MySQLConnection.get_characterset_info = MySQLConnection.get_charset patch() from sqlalchemy import MetaData, Table, Column, Integer, String, create_engine from gevent import spawn, sleep from random import randrange from time import time class Stats(object): def __init__(self): self.inserts, self.faults = 0, 0 def run(self): while True: sleep(1) print "%d %d %d" % (time(), self.inserts, self.faults) self.inserts, self.faults = 0, 0 class Victim(object): metadata = MetaData() Entry = Table( 'entry', metadata, Column('id', Integer, primary_key=True), Column('junk', String(128), unique=True) ) def __init__(self, cs, stats): self.e = create_engine(cs) self.metadata.drop_all(self.e) self.metadata.create_all(self.e) self.stats = stats def add(self, junk, i): print i, 'connecting' c = self.e.connect() print i, 'connected' t = c.begin() try: q = self.Entry.insert().values(junk=junk) c.execute(q) t.commit() self.stats.inserts += 1 except Exception as e: print i, 'EXCEPTION: ', e t.rollback() self.stats.faults += 1 print i, 'done' def flood(victim, i): a, z, l = ord('a'), ord('z')+1, 100 while True: victim.add(''.join(chr(randrange(a, z)) for _ in xrange(l)), i) sleep(0) def main(n_threads, cs): stats = Stats() victim = Victim(cs, stats) threads = [ spawn(flood, victim, i) for i in xrange(n_threads) ] threads.append(spawn(stats.run)) [t.join() for t in threads] #main(2, 'mysql://root:root@localhost/junk') main(1, 'mysql+mysqlconnector://root:root@localhost/junk') </code></pre> <p>What is happening?</p> <hr> <p>Retested, error persists without gevent, probably something with server configuration</p>
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    1. COJust to confirm, does "Any number of workers" include exactly 1 worker?
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    2. COYes (fixed question)
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