Re: EOF error

On Wednesday 27 February 2008 7:58 pm, johnf wrote:
> On Wednesday 27 February 2008 06:09:31 pm Chris Cogdon wrote:
> > On Feb 27, 2008, at 17:47 , johnf wrote:
> > > On Wednesday 27 February 2008 05:23:59 pm you wrote:
> > >> On Feb 27, 2008, at 15:37 , johnf wrote:
> > >>> I got similar results.  I also get an entry into the log
> > >>> "Abort"  when I use connection.close().  But I don't get anything
> > >>> when I use
> > >>> del connection.
> > >>
> > >> You have a transaction in progress at the time ? Ie, perhaps you did
> > >> some select statements inside read_serializable mode ?
> > >
> > > I doubt that.  I just open the connection and then make a select
> > > and close.
> >
> > That would be a transaction ;) It happens under the hood in most
> > (all?) python-postgresql connectors. Upon the first statement
> > executed, the connector will open up a transaction, even if it's a
> > simple select statement.
> >
> > So, I just repeated your experiment, with FULL debugging on, and I
> > get this:
> >
> > 2008-02-27 18:10:46 PST (25214)> LOG:  statement: ABORT
> >
> > and if I do a "rollback" or a "commit" before I try and close, then I
> > DONT get the ABORT.
> >
> > So, yeah, you're inside a transaction,even after a simple select.
>
> OK so what is a guy suppose to do?  It seems like a no win situation.

When in doubt read the docs (something I have a problem with ):)

Setting transaction isolation levels

psycopg2 connection objects hold informations about the PostgreSQL transaction 
isolation level. The current transaction level can be read from 
the .isolation_level attribute. The default isolation level is READ 
COMMITTED. A different isolation level con be set through 
the .set_isolation_level() method. The level can be set to one of the 
following constants, defined in psycopg2.extensions:

ISOLATION_LEVEL_AUTOCOMMIT
    No transaction is started when command are issued and 
no .commit()/.rollback() is required. Some PostgreSQL command such as CREATE 
DATABASE can't run into a transaction: to run such command 
use .set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT).
ISOLATION_LEVEL_READ_COMMITTED
    This is the default value. A new transaction is started at the 
first .execute() command on a cursor and at each new .execute() after 
a .commit() or a .rollback(). The transaction runs in the PostgreSQL READ 
COMMITTED isolation level.
ISOLATION_LEVEL_SERIALIZABLE
    Transactions are run at a SERIALIZABLE isolation level.


So you may or may not be in a transaction.
-- 
Adrian Klaver
[email protected]