On Tue, Jan 15, 2019 at 3:55 PM Wugang Xu <[email protected]> wrote:
>
> I am using sqlalchemy 0.9.8 on python 2.7 with Oracle database. I tried
> thread local strategy since we have lot of code acquiring a connection
> without closing the current ones, assuming that the new connection will be
> the same one as currently checked out connection.
the threadlocal strategy is being deprecated in 1.3 and I would not
advise new development using this flag. in particular, it has no
effect with typical use of an Engine object with explicit connections
unless you call upon the contextual_connect() method, which is also
going to go away around 1.4 or so. There are also a few stability
bugs in the threadlocal strategy that aren't going to be fixed.
> However, when I tested the following code, it wait on the seconds time
> acquiring connection from engine until timing out. It is the same thing when
> I tried contextual_connect instead of raw_connection. is there anything wrong
> with my code?
>
> from sqlalchemy import create_engine
>
> def _main():
> conn_str = ''
> engine = create_engine(conn_str, pool_size=1, max_overflow=0,
> pool_recycle=5, strategy='threadlocal')
> conn=engine.raw_connection()
> cur = conn.cursor()
> cur.execute('insert into wugang_test values(1)')
> cur.execute('commit')
> # conn.close()
> conn = engine.raw_connection()
> cur = conn.cursor()
> for r in cur.execute('select * from wugang_test'):
> print r
engine.raw_connection does not seem to be calling upon the thread
local context here so you won't get any threadlocal behavior with it.
only contextual_connect() should be doing that. it's also not
really a good idea to call "cursor.execute("commit")", the DBAPI has a
commit() method on the connection object that should be used for this
if you are working with raw DBAPI connections.
for contextual_connect(), the code should be working, here's a proof
of concept which only blocks if you remove the "threadlocal" part, so
try this out:
from sqlalchemy import create_engine
e = create_engine(
"mysql://scott:tiger@localhost/test",
pool_size=1,
max_overflow=0,
pool_recycle=5,
strategy="threadlocal",
)
conn = e.contextual_connect()
conn2 = e.contextual_connect()
assert conn.connection.connection is conn2.connection.connection
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
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--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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