Re: [S] Re: Problems with non scrollable cursors

Kris Jurka wrote:

>On Fri, 21 Jan 2005, Daniele Bufarini wrote:
>
>
>
>>I'm developing a web application. I haveto know exactly how many pages I
>>have and I have to allow the user to jump to a specific page( this is
>>where I used limit and offset): I know that this solution is VERY slow
>>and I tried to use cursors.... BUT (from PostgreSQL docs):
>>" The Statement must be created with a ResultSet type of
>>ResultSet.TYPE_FORWARD_ONLY. This is the default, so no code will need
>>to be rewritten to take advantage of this, but it also means that you
>>cannot scroll backwards or otherwise jump around in the ResultSet." !!!
>>So I cannot, for example, use the ResultSet.absolute() to jump back in
>>the result set!
>>
>>
>
>You are kind of out of luck.  The only way a scrollable cursor will be
>faster than a limit/offset is if you use it multiple times.  To use it
>multiple times you need to keep this cursor open across numerous page
>requests.  This is a complicated piece of backend state because it may
>take up significant server resources and then there is the business of
>"finding" this cursor again when the user comes back.  Are you really
>going to try and keep an open database connection for every user?  Not in
>any web app that I know.
>
>Kris Jurka
>
>

Actually using the cursor multiple time is what I was thinking...
In fact, I can keep an open database connection only for large result
set and use a one time connection for all the others.
My problem is that I cannot scroll back using a cursor... I'm wondering
If I have to modify the jdbc driver or the back end or if there are
other solutions, less time consuming...

        Daniele Bufarini


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| Daniele Bufarini          Informazioni Editoriali I.E. S.p.A.   |
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