Re: Thinking out loud about a new RPG web framework

[Thorbjørn Ravn Andersen <thunderaxiom@xxxxxxxxx>]

Joe Pluta skrev  den 06-06-2008 17:42:
> Since JDBC 3.0 allows for moving both back and forth in a resultset 
> (this is from memory, so the names may be different) I would use plain 
> SQL over JDBC and put the resultset in the session bean along with a 
> counter stating the current row number so paging is possible.  It should 
> be trivially simple, but I'll need to do a quick and dirty test to see 
> if it actually is so :)
>   
>   
> As far as I know, scrollable resultsets cannot be placed in stateless 
> session beans.
>
> Please, try it out.  Let us know.
>   
This turned out to be both an interesting exercise and a learning 
experience regarding different .  It is not a problem to store a 
scrollable resultset as a session attribute in JSP and navigate back and 
forth with a PostgreSQL database on OpenSolaris so that was working nicely.

It then turned out that the PostgreSQL JDBC driver loads the complete 
resultset in memory when needing to be able to page back and forth, 
which was the whole idea to avoid so that was an unpleasant surprise 
having 11 million rows in my testset.  So now I've learned that not all 
JDBC-drivers are created equal :)

After looking at the jtOpen version 5.0 code it appears that this is 
only possible for V5R3 and above, and it appears that this will be 
implemented with cursors as I expected (but the code is quite hard to read).

I will give it a try when I have time again and see how it performs 
against the i.  It takes a while to load the dataset...