Re: Suspending SELECTs

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Craig A. James wrote:

Alessandro Baretta <a.baretta@xxxxxxxxxxxxxxx> writes:

I think you're trying to do something at the wrong layer of your architecture. This task normally goes in your middleware layer, not your database layer.

I am developing my applications in Objective Caml, and I have written the middleware layer myself. I could easily implement a cursor-pooling strategy, but there is no perfect solution to the problem of guaranteeing that cursors be closed. Remember that web applications require the user to "open a session" by connecting the appropriate HTTP resource, but users as never required to log out. Hence, in order to eventually reclaim all cursors, I must use magical "log-out detection" algorithm, which is usually implemented with a simple timeout. This guarantees the required property of safety (the population of cursors does not diverge) but does not guarantee the required property of liveness (a user connecting to the application, who has opened a session but has not logged out, and thus possesses a session token, should have access the execution context identified by his token).

Alex



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