Re: Thinking out loud about a new RPG web framework

Joe Pluta skrev den 09-06-2008 19:30:

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.

I did not advocate against stateful designs. I advocated against having statefulness more than one place, and you said that I could not create an application which could page the result of an arbitrary SQL command without recreating the query every time. Hence this is what I am looking at creating a proof-of-concept for.

Connection pools should grow and shrink as needed.

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.

Or the database would be smart enough to keep the query active and allow the resultset to navigate. This is currently what I expect the i to be able to.

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Thorbjørn