Hi.
I have found some problems with threadlocal strategy and the ResultProxy.
Here is the code that reproduces the problem, Twisted and PostgreSQL are
required.
I'm using SQLAlchemy 0.3.6-1 from Debian Etch.
I don't know if this is a bug of SQLAlchemy.
Is the ResultProxy thread safe?
#! /usr/bin/env python
import sys
from twisted.python import log
from twisted.internet import defer, threads, reactor
import sqlalchemy as sq
def callback(result, i):
# Is the ResultProxy thread safe?
if USE_CURSOR:
rows = list(result)
log.msg('callback', i)
def errback(reason):
log.err(reason)
def f():
l = []
for i in range(N):
log.msg('request', i)
d = threads.deferToThread(db.execute, QUERY)
d.addCallbacks(callback, errback, callbackArgs=(i,))
l.append(d)
return defer.DeferredList(l)
def main():
return f().addCallbacks(lambda _: None, lambda r: log.err(r)
).addBoth(lambda _: reactor.stop())
POOL_SIZE = 1
N = 10
QUERY = 'SELECT CURRENT_TIMESTAMP'
URL = 'postgres://manlio:[EMAIL PROTECTED]/test'
STRATEGY = 'threadlocal'
USE_CURSOR = False
reactor.suggestThreadPoolSize(POOL_SIZE)
db = sq.create_engine(URL, pool_size=POOL_SIZE, strategy=STRATEGY,
echo_pool=False)
log.startLogging(sys.stdout)
reactor.callWhenRunning(main)
reactor.run()
When USE_CURSOR is False, I got (at random) the error:
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 718,
in execute
connection = self.contextual_connect(close_with_result=True)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/threadlocal.py",
line 148, in contextual_connect
return self.session.get_connection(**kwargs)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/threadlocal.py",
line 21, in get_connection
return TLConnection(self, close_with_result=close_with_result)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/threadlocal.py",
line 63, in __init__
base.Connection.__init__(self, session.engine,
close_with_result=close_with_result)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 368,
in __init__
self.__connection = connection or engine.raw_connection()
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/threadlocal.py",
line 127, in raw_connection
return self.connection_provider.get_connection()
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/default.py", line
19, in get_connection
return self._pool.connect()
File "/usr/lib/python2.4/site-packages/sqlalchemy/pool.py",
line 150, in connect
return
self._threadconns[thread.get_ident()].connfairy().checkout()
exceptions.AttributeError: 'NoneType' object has no attribute
'checkout'
When USE_CURSOR is True, I obtain (at random) any of these two errors:
File "./concurrency.twisted.py", line 12, in callback
rows = list(result)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 921,
in __iter__
row = self.fetchone()
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 997,
in fetchone
self.close()
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 862,
in close
self.cursor.close()
File "/usr/lib/python2.4/site-packages/sqlalchemy/pool.py",
line 312, in close
if self in self.__parent._cursors:
exceptions.TypeError: iterable argument required
and:
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 719,
in execute
return connection.execute(statement, *multiparams, **params)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 444,
in execute
return Connection.executors[c](self, object, *multiparams,
**params)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 458,
in execute_text
cursor = self._execute_raw(statement, parameters)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/engine/base.py", line 540,
in _execute_raw
cursor = self.__engine.dialect.create_cursor(self.connection)
File
"/usr/lib/python2.4/site-packages/sqlalchemy/databases/postgres.py",
line 277, in create_cursor
return connection.cursor()
File "/usr/lib/python2.4/site-packages/sqlalchemy/pool.py",
line 253, in cursor
self.invalidate()
File "/usr/lib/python2.4/site-packages/sqlalchemy/pool.py",
line 243, in invalidate
raise exceptions.InvalidRequestError("This connection is
closed")
sqlalchemy.exceptions.InvalidRequestError: This connection is
closed
Thanks and regards Manlio Perillo
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To post to this group, send email to sqlalchemy@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/sqlalchemy?hl=en
-~----------~----~----~----~------~----~------~--~---
