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Re: Point at which WAN latency affects perceived app response?

From: sphealey <>
Date: 15 Sep 2006 14:48:06 -0700
Message-ID: <>

> Ian M wrote:
> > Does anyone have any experience with the effect of WAN latency on
> > applications accessing an Oracle database over a WAN?
> >
> We had some problems with issues like this a year back when we were
> transferring an applications from a LAN to a WAN (our latency went from 0/1
> to 7/8 ms). I must say the idea of moving to a latency of such a change
> based on the experience we have had is a cause for concern and you are right
> to question it.
> [...]
> In the end the MS Access application was repaired by converting external
> table based queries into a single Oracle View and also amending the Prefetch
> count to 20000 on the ODBC settings which had the effect of a network
> buffer.
> For the Oracle Forms application a re-write of the application was required
> to remove the tiny looped database lookups (sigh).
> In both cases after the changes the applications performed much better on
> the old LAN than the same copy moved onto the new WAN but this was similar
> to the older unchanged application performance and thus was acceptable to
> the business.
> Basically latency is a killer if your application is not WAN friendly test,
> test and if in doubt test.
> I hope the information helps and good luck with it.

Thanks for sharing that experience; it sounds as if you have already been down this road. I will follow up on your suggestions.

The problem of course is that the primary application is packaged and we have no control over its design, which is known to use suboptimal SQL and database programming techniques.

Is there any way to control the ARRAY_SIZE parameter outside of the application code?

sPh Received on Fri Sep 15 2006 - 16:48:06 CDT

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