Re: Consecutive Inserts Freeze Execution of Psycopg3

On 4/23/23 14:55, Michael P. McDonnell wrote:
> That helped a ton, I don't understand why I've had to rewrite the crap
> out of all of this to get it to work (dropping SqlAlchemy, upgrading
> from psycopg2 to psycopg, etc...) but it's working now and I can work
> around it. Thank you.

Well:

1) SQLAlchemy is an ORM that tries to make all databases look the same.

2) psycopg2 != psycopg. For details see:

https://www.psycopg.org/psycopg3/docs/basic/from_pg2.html

3) It would have been more of a surprise if you did not have to change
anything.

4) And this

with self.connection.cursor() as conn:

was just plain wrong. You where trying to make a cursor be a connection
and that is not going to work.

>
>
> On Sun, Apr 23, 2023 at 4:25 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>> wrote:
>
> On 4/23/23 13:45, Michael P. McDonnell wrote:
> > Python 3.10.6
> > psycopg library 3.1.8
> >
> > Running consecutive inserts sourced in files.
> > All inserts are of the same format:
> >
> > INSERT INTO _____ (field1, field2, field3)
> > SELECT field1, field2, field3 FROM ____, Join ___, join ___ etc...
> >
> > The code I've written is this:
> >
> > for qi in range(qlen):
> >              query = queries[qi]
> >              qparams = params[qi]
> >              with self.connection.cursor() as conn:
> >                  conn.execute(query, qparams)
>
> In above you are running the context manager(with) over the cursor not
> the connection. This will not automatically commit the transaction. You
> will need to either explicitly do connection.commit() or use the with
> over the connection per:
>
> https://www.psycopg.org/psycopg3/docs/basic/transactions.html
> <https://www.psycopg.org/psycopg3/docs/basic/transactions.html>
>
> >
> > When I run the queries in dbeaver - the first query takes 120s (it's
> > 1.9M rows), the second query takes 2s (7000 rows).
> > When I run the queries in python - it freezes on the second query.
> >
> > Any guidance on how to attack this would be awesome as I have
> re-written
> > my code a dozen times and am just slinging mud to see what sticks.
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com