Thanks Andrea for the answer,
I'm not sure if i fully understood what you mean, i'm not running any specific query, i'm using just the REST calls, i don't know if there is any specific data store configuration. Can u let me know how can i check this?
I just noted that there is a lot of postgres activities before the layer is rendered and also the default polygon style takes a while to render the layer.
here is the URL with the default polygon SLD (it takes a long time):
http://fenix.fao.org:8050/geoserver/wms?service=WMS&version=1.1.0&request=GetMap&layers=fenix:prj_445744375&styles=polygon&bbox=-180.0,-55.9794960021973,180.0,83.1106185913086&width=854&height=330&srs=EPSG:4326&format=application/openlayers
here is the URL that uses the SLD with the classes (it takes a long time):
http://fenix.fao.org:8050/geoserver/wms?service=WMS&version=1.1.0&request=GetMap&layers=fenix:prj_445744375&styles=&bbox=-180.0,-55.9794960021973,180.0,83.1106185913086&width=854&height=330&srs=EPSG:4326&format=application/openlayers
and also using the World layer (that contains more polygons), the rendering is much faster:
http://fenix.fao.org:8050/geoserver/wms?service=WMS&version=1.1.0&request=GetMap&layers=fenix:zzlayer_gaul0&styles=polygon&bbox=-180.0,-89.9,180.0,83.627&width=684&height=330&srs=EPSG:4326&format=application/openlayers
Do you have any idea? 
Thanks again,
Simone
________________________________________
Da: andrea.aime@...84... [andrea.aime@...84...] per conto di Andrea Aime [andrea.aime@...1107...]
Inviato: lunedì 18 aprile 2011 10.22
A: Murzilli, Simone (ESA)
Cc: geoserver-users@lists.sourceforge.net
Oggetto: Re: [Geoserver-users] SLD class creation issue
On Mon, Apr 18, 2011 at 10:00 AM, Murzilli, Simone (ESA)
<Simone.Murzilli@...672...> wrote:
Hi to all,
I'm quite new to GeoServer (currently using the 2.1 RC3 version), i have a few questions about SLDs.
I'm styling a vector layer that has many polygons on which i project data which covers a numeric range. When the data range is really large (i.e. from 1-9Bil) the time it takes to render the layer is really long and i can see a lot of postgres processes running. Conversley, when the data range is small (i.e 1-100) the rendering is very fast.
Also the number of classes generated (6) is equal regardless of the data range.
Is there a way of optimizing the SLDs classes creation when the data range is large? The SLD is generated using the GeoServer SLD Service which uses the following rule:
<sld:Rule>
<sld:Title> > 153.45 AND <= 291.42</sld:Title>
<ogc:Filter>
<ogc:PropertyIsLessThanOrEqualTo>
<ogc:Literal>291.42</ogc:Literal>
<ogc:PropertyName>quantity</ogc:PropertyName>
</ogc:PropertyIsLessThanOrEqualTo>
</ogc:Filter>
<sld:PolygonSymbolizer>
<sld:Fill>
<sld:CssParameter name="fill">#E6AA91</sld:CssParameter>
</sld:Fill>
</sld:PolygonSymbolizer>
</sld:Rule>
Maybe i'm missing something quite obvious, any help would be most appreciated
I'd check if the data store configuration uses prepared statements. If
so, please go and disable them.
Prepared statements offer better security against sql injection and
some performance improvement
if the queries made are all "similar", but if you mix very selective
queries with ones that are not
the database is probably going to make a wrong choice of access plan.
In your case it probably
decided to use an index based on the interval filter, but if the
interval is very large, not selective
at all, that choice is going to be very poor
Cheers
Andrea
--
-------------------------------------------------------
Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 962313
mob: +39 333 8128928
http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.youtube.com/user/GeoSolutionsIT
http://www.linkedin.com/in/andreaaime
http://twitter.com/geowolf
-------------------------------------------------------