WFS performance issue

[Yewondwossen Assefa]

Frank Warmerdam wrote:
> On Thu, 24 Mar 2005 10:24:39 -0500, Yewondwossen Assefa
> <assefa at dmsolutions.ca> wrote:
>
>>   I understand the this way of implementing complexe filters is not the
>>most optimal but Filters can become so complex that I need some kind of
>>logic and limitation to be able to adress all the cases.
>
>
> Assefa,
>
> As I understand it, we only have the opportunity for one SQL query
> to be evaluated in the RDBMS via the FILTER operator on a layer.
> What I would suggest is that if you find the query to be simple -
> that is a single bbox and/or one set of simple property operations then
> you convert the attribute queries into a  FILTER and let the underlying
> provider take care of it.
>

  Agreed. But there is even a limit when there is BBOX in the Filter. If
the BBOX is bundled with other opreations using the OR or Not operators,
the will necessite 2 separate queries. In case it is an AND I will
consider it as a simple filter.

> In all other circumsances just fallback to the existing approach
> which we have confidence works for complex cases.  So we would
> basically just optimize simplier queries.
>

  Agreed.


Thanks,

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Assefa Yewondwossen
Software Analyst

Email: assefa at dmsolutions.ca
http://www.dmsolutions.ca/

Phone: (613) 565-5056 (ext 14)
Fax:   (613) 565-0925
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