Re: streaming result sets: progress - Mailing list pgsql-jdbc

On Monday 18 November 2002 05:14 pm, Barry Lind wrote:
> Nic,
>
> Here are my thoughts on this topic.
>
> 1) Since the server doesn't support cursors across transactions, I don't
> think the driver should either.  In fact in jdbc3 the DatabaseMetaData
> object has a supportsResultSetHoldability() method that explicitly lets
> the driver tell the application what is does/doesn't support in this area.
>
> I think running multiple sql statements to mimic this behavior is a very
> bad idea.  Since the select statements will run at different times they
> will return different data (since they will pick up commited changes
> between runs), and if you don't include an order by the results are
> completely unpredictable.  If someone wants this very unpredictable
> behavior they can issue the multiple statements themselves.
>
> 2) I think the use of cursors should be optional.  In fact since most
> queries don't need them since most queries return a small number of rows
> , I think the use of cursors needs to be turned on.  I think there
> should be two ways to do this:  the first is by setting the fetchSize()
> and the second would be a jdbc url parameter.
>
> 3) I think the transaction characteristics of the current patch are just
> fine and conform to the jdbc specification.  The code should
> automatically close the resultset when a commit occurs.  One thing that
> will be confusing is that noncursor based result sets will work accross
> commits, but cursor based ones won't.  But I think that is reasonable.

My problem :
master-detail
I select one from many rows master with cursor (big table and only this is possible)
- In detail I do change and commit (or rollback)
My select is lost.
How can I do that ?

> Nic Ferrier wrote:
> > Message-ID: <87fztyexea.fsf@pooh-sticks-bridge.tapsellferrier.co.uk>
> > Lines: 24
> > MIME-Version: 1.0
> > Content-Type: text/plain; charset=us-ascii
> > --text follows this line--
> >
> > Haris Peco <snpe@snpe.co.yu> writes:
> >>I have tried.
> >>DatabaseMetaData is fine, but ResultSet.[get|set]FetchSize don't
> >>work
> >
> > What error do you get?
> >
> >>Prepared command don't work, but my greatest problem are trasnaction
> >>I hope that cursor in 7.4 will be out of a transaction
> >
> > I don't think there's much I can do about the cursor problem.
> >
> >>Can Yoy yet another :
> >>set driver's flag btw jdbc:pgsql:...?cursor=yes
> >>for use cursor or old way
> >
> > What does everyone else think? Is a system doing a different query
> > each time worth looking into?
> >
> >
> > Nic
> >
> >
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