I'm restarting it after the first fetchall() finishes.
My experience with postgresql/psycopg2 is that you can tell the
connection is dead when you next try to call cursor(), but that isn't
happening here because of the queue problem I described.
Here's the output with pool logging on, if that helps:
>>> e = create_engine('postgres://[EMAIL PROTECTED]/mozy', pool_size=1,
max_overflow=0, pool_timeout=None, echo=True)
>>> e.execute('select 1').fetchall()
>>> 2007-01-25 15:03:10,704 INFO sqlalchemy.pool.QueuePool.0x..b4
Created new connection <connection object at 0xb79ca020; dsn:
'dbname=mozy host=db user=neptune', closed: 0>
INFO:sqlalchemy.pool.QueuePool.0x..b4:Created new connection
<connection object at 0xb79ca020; dsn: 'dbname=mozy host=db
user=neptune', closed: 0>
2007-01-25 15:03:10,704 INFO sqlalchemy.pool.QueuePool.0x..b4
Connection <connection object at 0xb79ca020; dsn: 'dbname=mozy host=db
user=neptune', closed: 0> checked out from pool
INFO:sqlalchemy.pool.QueuePool.0x..b4:Connection <connection object at
0xb79ca020; dsn: 'dbname=mozy host=db user=neptune', closed: 0>
checked out from pool
2007-01-25 15:03:10,705 INFO sqlalchemy.engine.base.Engine.0x..14 select 1
INFO:sqlalchemy.engine.base.Engine.0x..14:select 1
2007-01-25 15:03:10,705 INFO sqlalchemy.engine.base.Engine.0x..14 None
INFO:sqlalchemy.engine.base.Engine.0x..14:None
2007-01-25 15:03:10,709 INFO sqlalchemy.pool.QueuePool.0x..b4
Connection <connection object at 0xb79ca020; dsn: 'dbname=mozy host=db
user=neptune', closed: 0> being returned to pool
INFO:sqlalchemy.pool.QueuePool.0x..b4:Connection <connection object at
0xb79ca020; dsn: 'dbname=mozy host=db user=neptune', closed: 0> being
returned to pool
[(1,)]
# [db restarted]
>>> e.execute('select 1').fetchall()
2007-01-25 15:03:30,690 INFO sqlalchemy.pool.QueuePool.0x..b4
Connection <connection object at 0xb79ca020; dsn: 'dbname=mozy host=db
user=neptune', closed: 0> checked out from pool
INFO:sqlalchemy.pool.QueuePool.0x..b4:Connection <connection object at
0xb79ca020; dsn: 'dbname=mozy host=db user=neptune', closed: 0>
checked out from pool
2007-01-25 15:03:30,691 INFO sqlalchemy.engine.base.Engine.0x..14 select 1
INFO:sqlalchemy.engine.base.Engine.0x..14:select 1
2007-01-25 15:03:30,691 INFO sqlalchemy.engine.base.Engine.0x..14 None
INFO:sqlalchemy.engine.base.Engine.0x..14:None
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "/root/SQLAlchemy-0.3.4/lib/sqlalchemy/engine/base.py", line
686, in fetchall
for row in self.cursor.fetchall():
psycopg2.ProgrammingError: no results to fetch
>>> e.execute('select 1').fetchall()
# [hangs]
On 1/25/07, Michael Bayer <[EMAIL PROTECTED]> wrote:
>
> if you close all connections (i.e. return them all to the pool), and
> then go to get them again, it can handle a restart *if* the dialect
> knows how to detect the conditions whereby it should invalidate() the
> connections. which is generally pretty spotty, i dont think PG knows
> how to do it. also i dont understand the error condition you are
> getting, the connections should all be getting returned above ( or some
> exception would be thrown).
>
> are you stopping the DB while the first fetchall() is executing ? or
> in between ?
>
>
> On Jan 25, 3:54 pm, "Jonathan Ellis" <[EMAIL PROTECTED]> wrote:
> > from sqlalchemy import *
> > e = create_engine('postgres://...', pool_size=1, max_overflow=0,
> > pool_timeout=None)
> > e.execute('select 1').fetchall()
> > # restart db
> > e.execute('select 1').fetchall()
> > # error gets raised, ConnectionRecord apparently doesn't get returned
> > to pool because:
> > e.execute('select 1').fetchall()
> > # hangs, pool overflow=1 (so new CR is not created) but nothing is in the
> > queue
>
>
> >
>
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