Well seems like the "stream_results" feature must be extremely unpopular
because I can confirm this behavior even using connection-local execution
options, in 0.7 also. This feature is tested so will have to see exactly
what's up with those tests.
On Apr 29, 2013, at 9:49 AM, Pau Tallada <tall...@pic.es> wrote:
> Hi,
>
> I have some very big datasets that we want to process in batches of
> reasonable size.
> In order to do that, we enable the 'stream_results' execution option
> (available in Postgresql) and we use the fetchmany method to retrieve the
> records in batches.
> With those records we must build a numpy array, but its constructor complains
> about the RowProxy wrapper.
>
> So I tried using the cursor directly to retrieve the selected rows, but the
> cursor skips the first one if 'stream_results' is enabled.
>
> Let me explain with an example:
>
> engine = create_engine(db_url, execution_options = {'stream_results' : True})
>
> rs = engine.execute("SELECT * FROM table")
> print len(rs.fetchall())
>
> rs = engine.execute("SELECT * FROM table")
> print len(rs.cursor.fetchall())
>
> The first one displays N, while the second one displays N-1.
>
> Any clues? :/
>
> Thank you in advance!
>
> Pau.
>
> --
> ----------------------------------
> Pau Tallada Crespí
> Dep. d'Astrofísica i Cosmologia
> Port d'Informació Científica (PIC)
> Tel: +34 93 586 8233
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>
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