yes but the schema is different for each run, I dont want it to be hard 
coded into the table definition.
 

On Tuesday, June 2, 2015 at 12:52:22 PM UTC+3, eli rashlin wrote:
>
> Hi,
>
> I have a very strange behavior, I have a program that uses bulk insertions 
> to the DB.
> for some reason the process which iterate on one table and create bulk and 
> insert into another table fails with the error of  'No database selected'.
>
>
> this is how I bind the session:
>
>
> #-------------------------------------------------------------------------------------------------------------------
> # use_db: 
> #        this method will return a session reference
> #         using this DB
> #-------------------------------------------------------------------------------------------------------------------
>     
>     
>     def use_db(self, new_db_name):
>         self.connection.execute("USE %s" % (new_db_name))
>         session_ref = sessionmaker(bind = self.connection, 
> expire_on_commit=False)
>         self.session_cover_tst = session_ref()
>         return self.session_cover_tst
>
>
>
> engine = connection_engine.use_db(db_name)
> count_sig = 
> engine.query(func.count(distinct(signals_table.Signals.sig_value)).label('count_sig')).\
>                                                                     
>  filter(signals_table.Signals.message_id == msg_row.id).\
>                                                                     
>  filter(signals_table.Signals.signal_id == sig_id).\
>                                                                     
>  group_by(signals_table.Signals.signal_id).\
>                                                                     
>  one()[0]
>
>
> now the table Signals is huge (500M records), but the table is indexed and 
> everything is working great for a few rounds and then I'm getting the 
> error  'No database selected'  and it fails...
>
>

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