Subject | Re: [IBO] IOBQuery |
---|---|
Author | Robert martin |
Post date | 2005-03-08T20:10:01Z |
Hi Jason
My screen simply displays a grid of data (allowing a user to reprint a
transaction). At sounds like this may have an impact on performance,
what could I do to minimise this, bearing in mind I dont want to suck
down all records unless a user scrolls down through the list?
Rob Martin
Software Engineer
phone +64 03 377 0495
fax +64 03 377 0496
web www.chreos.com
Wild Software Ltd
Jason Wharton wrote:
My screen simply displays a grid of data (allowing a user to reprint a
transaction). At sounds like this may have an impact on performance,
what could I do to minimise this, bearing in mind I dont want to suck
down all records unless a user scrolls down through the list?
Rob Martin
Software Engineer
phone +64 03 377 0495
fax +64 03 377 0496
web www.chreos.com
Wild Software Ltd
Jason Wharton wrote:
>>Thanks exactly what I wanted to hear.
>>
>>
>
>However, this may not be...
>
>Keep in mind you should not have a query open any longer than necessary in
>this circumstance. When you have a large dataset and the query has only
>fetched a portion of it then a cursor must be maintained on the server to
>keep the queue of records ready for when the fetches come. This cursor on
>the server does use resources and it also requires the physical transaction
>on the server be maintained to preserve the cursor as well, thus you are
>forcing a transaction handle to remain issued on the client until that
>dataset is either closed or all the records are fetched in full.
>
>What IBO does with a dataset where all records are not fetched is it starts
>using idle cycles and fetches in records feeling for the end of the dataset
>in hopes that it can keep the OAT to advance and keep up. Thus, you could
>actually have it such that your datasets start scooping up lots of virtual
>ram and your users may notice these blips when records are being fetched in
>if their PC's are low-end machines.
>
>Jason Wharton
>
>
>
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