[Chameleon] Map refresh slower at bigger scale

[Federica De Martin]

Hi,
I've got a Chameleon application that takes data from a big Postgis database
(a dump of 300MB). My problem is that the refresh of the map takes much more
time when I am at a bigger scale. For example with the same layer activated:
-if I am at scale 1:100.000  and I zoom to scale 1:5.000 the refresh takes
more or less 10 seconds
-if I am at scale 1:5.000  and I zoom to scale 1:1.000 the refresh takes
around 30 or more seconds (it depends on the number of object in the area)
What I would like to understand is why there is so much difference in the
drawing time of this two maps. Why is the second dwawing time greater then
the first drawing time? I was expecting exactly the contrary, is it normal
or is there something wrong in my mapfile or somewhere else?

Do you know what I can check to solve this problem? And can you suggest me
how I can make my application faster?
Thank you all in advance.
Federica
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