Re: [gnome-db] Questions about a possible asynchronous gda behaviour

[Gonzalo Paniagua Javier <gonzalo gnome-db org>]

El mar, 11-11-2003 a las 12:50, David Marín Carreño escribió:
> Hi.
> 
> I'd like to know what is the gda behaviour while querying a PostgreSQL
> server. 
> 
> Is it asynchronous? That is: the query is launched with
> "gda_connection_execute_single_command", but this function returns after
> making the query, without waiting for the datamodel to be filled with
> the real data. The application should block when trying to access to
> datamodel rows not filled yet, and should unblock when these rows get
> the real data.

No, it's not.

> 
> I don't know if this is the actual behaviour, but if it isn't, IMHO, I
> think it's a necessary feature: when a program has to show a very long
> list of data, I cannot wait until having all the rows before starting to
> show the first of them.
> 
> I know that PostgreSQL, with libpq, support this behaviour
> (http://www.postgresql.org/docs/7.3/interactive/libpq-async.html), where
> you make a query, and then ask libpq for data a lot of times until all
> the data has been sent.

We may add an option to GdaCommandOptions that tells the provider we
want async processing. Then we have to add a function to be called when
the system is idle that reads any data available and stores it in the
GdaDataModel you get. The connection is locked for anything else while
this has not finished.

Would you please file a bug report in bugzilla asking for this?

You may find
http://www.postgresql.org/docs/7.3/interactive/queries-limit.html useful
by now.

-- 
Gonzalo Paniagua Javier <gonzalo gnome-db org>
http://www.gnome-db.org/~gonzalo/