Hi there,
Thanks for the clarity, much appreciated ;-)
Lynton
On Mar 9, 5:25 pm, "Michael Bayer" <mike...@zzzcomputing.com> wrote:
> Lynton Grice wrote:
> > Hi Michael,
>
> > Can you paste the following code into your editor and try it out? Can
> > you tell me what I would need to do to close the connections in this
> > case?
>
> I think when using SQLite, your best bet is to use NullPool in any case
> which will eliminate the issue and even remove the need for calling
> engine.dispose(). Though you will need to call session.close() at the
> end to release the connection.
>
> As far as StaticPool I would qualify what's happening here as a bug in
> SQLAlchemy. engine.dispose() dumps the current pool and creates a new
> one. StaticPool is the *one* pool that connects immediately when it is
> first created, so that is why a connection is hanging around here. The
> change needs to be that StaticPool only creates a connection when first
> used, like all the other pools so I've added #1728 for that.
>
>
>
>
>
> > Any help would be greatly appreciated ;-)
>
> > from sqlalchemy import *
> > from sqlalchemy.orm import sessionmaker
> > from sqlalchemy.orm import mapper
> > from sqlalchemy.pool import StaticPool
> > import os
>
> > class Message(object):
> > pass
>
> > if __name__ == '__main__':
> > db_conn = 'sqlite:///foo.db'
> > db = create_engine(db_conn,echo=False, poolclass=StaticPool)
> > metadata = MetaData(db)
> > queueName = 'foo'
> > queue = Table(queueName, metadata,
> > Column('IDX', Integer, primary_key=True,
> > autoincrement = True ),
> > Column('ID', String(64)),
> > Column('CORRELATIONID', String(64)),)
> > queue.create()
> > session_maker = sessionmaker(bind=db)
> > session = session_maker()
> > mapper(Message, queue)
>
> > msg = Message()
> > msg.ID = '1234'
> > msg.CORRELATIONID = '111'
> > session.add(msg)
> > session.commit()
>
> > print "Message count: " + str(session.query(Message).count())
>
> > db.dispose()
> > os.remove('foo.db')
> > print "Done..."
>
> > Thanks
>
> > Lynton
>
> > On Mar 8, 4:41�pm, "Michael Bayer" <mike...@zzzcomputing.com> wrote:
> >> Lynton Grice wrote:
> >> > Hi there,
>
> >> > I am using SQLAlchemy to build a custom based queue implementation.
>
> >> > As part of the methods exposed I have a "deletequeue" that is meant to
> >> > physically delete the SQLite database from the file system.
>
> >> > But whenever I try delete it I get the following error:
>
> >> > WindowsError: (32, 'The process cannot access the file because it is
> >> > being used by another process'
>
> >> > I have tried calling the DISPOSE method of the ENGINE object from
> >> > SQLAlchemy but there is still some file handle holding on...
>
> >> > All I have done is create the database (.db file), and now I want to
> >> > delete it but no luck ;-(
>
> >> > Any ideas how I can close any "handles" referencing that ".db" file
> >> > for that SQLite database?
>
> >> here is a test that passes for me, however even if I don't close the
> >> connection or dispose the engine the file still allows deletion. � Your
> >> first step is to ensure this program works on your platform.
>
> >> from sqlalchemy import *
>
> >> engine = create_engine("sqlite:///foo.db")
>
> >> conn = engine.connect()
> >> conn.execute("create table foo (bar string)")
> >> conn.execute("insert into foo values('test')")
> >> conn.close()
> >> engine.dispose()
>
> >> import os
> >> os.remove('foo.db')
>
> >> > Thanks for the help
>
> >> > Lynton
>
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