if you want to go that route I'd use the connection events to hit every DBAPI
connection as it's created, and store them in a weak-referencing collection:
import weakref
from sqlalchemy import event
from sqlalchemy.engine import Engine
connections = weakref.WeakKeyDictionary()
@event.listens_for(Engine, "connect")
def connect(dbapi_conn, conn_rec):
connections[dbapi_conn] = True
# this would run in a worker thread or other asynchronous system
def refresh():
for conn in connections:
cursor = conn.cursor()
cursor.execute("select 1")
cursor.close()
there's a slight chance of unsupported concurrent access with the above
pattern, esp. if you're using a non-threadsafe DBAPI like MySQLdb. If so, you
might want to also keep track of connections as they are checked out and
checked in using the "checkin", "checkout" events, and only do the "ping" if a
connection is not in "checkout" state.
On Dec 23, 2012, at 11:03 AM, Alexey Vihorev wrote:
> Hi, all!
> I’ve got a problem in my GUI app – if a connection stayes open for too long,
> and is inactive (user opened an editing window and went away for a cofee
> brake etc), firewall/other network machinery will close the connection and
> the session will fail with ’connection abnormally terminated’. So I’m trying
> to come up with a best way to handle that, and for now I’ve settled with
> using timer and executing session.connection().execute('select now()') every
> minute or so, but that requires handling of each session\connection
> individually. Can I get a list of all open connections for an engine, iterate
> over them and do execute('select now()')? Thanks.
>
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