alchemy_bad_performance.py

# -*- coding: utf-8 -*-

import threading
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, scoped_session

engine = create_engine("mysql://testing:[email protected]/testing",
                   pool_size=20, strategy="threadlocal")
Session = scoped_session(sessionmaker(bind=engine))

def query():
    sess = Session()
    res = sess.execute("SELECT SLEEP(1);")
    print threading.currentThread().getName()
    print "    :%s" % (tuple(res),)
    sess.close()


print "Spawning threads"
threads = [threading.Thread(target=query) for n in range(10)]
for thread in threads:
    thread.start()

for thread in threads:
    thread.join()
    print "%s complete" % thread.getName()

print "Terminating"