Re: Thinking out loud about a new RPG web framework

[Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>]

Thorbjørn Ravn Andersen wrote:
> 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.
>   
Hold on though - this means you need a stateful HTTP session, right?  
That is, you keep the database connection from one request to the next.  
If you have that and 1000 users, and you all use a connection pool with 
only 100 entries, then the pool will run out of connections.  It's 
basically a stateful design.

> 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 :)
>   
I expected this.  If the result set is truly disconnected, then you 
would have to either hold all the data in memory, or else you have to 
create a new index each time.

Now, you may have a really smart result set that can handle paging, but 
it will require a stateful connection.  That's why I say that putting 
the resultset in the JSP session is cheating: you cannot release the 
connection back to the pool, so you are in effect entirely stateful.  
Whether your stateful connection is a JDBC connection or an AS400 object 
makes no difference.

Joe