I have checked, it is an issue of BasicFeatureRenderer of UDIG. So nothing
to be hacked in GeoTools, but an option is desired in UDIG.

Vitali.

> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:geotools-devel-
> [EMAIL PROTECTED] On Behalf Of Andrea Aime
> Sent: Wednesday, August 29, 2007 3:55 PM
> To: Vitali Diatchkov
> Cc: 'geotools-devel'
> Subject: Re: [Geotools-devel] Various rendering speedups in,feedback
> appreciated
> 
> Vitali Diatchkov ha scritto:
> >
> > Just a hint from my mind related to our projects.
> >
> > There are situations when 20 layers from Oracle are being rendered. The
> data
> > is spread among the whole territory of Finland and the often situation
> is
> > when there is no data to be rendered at the specified scale ratio for 17
> of
> > 20 layers. But every renderer not only requests features but also calls
> > getCount() method to perform real checking to be sure that there is no
> data
> > to be rendered if empty feature collection has come in the beginning.
> > getCount() leads to "SELECT count(*) FROM.. WHERE.." and so on in case
> of
> > OracleDataStore - for these 17 layers from 20. Totally we have 3 + (17 *
> 2)
> > requests to the database (if we have 20 layers and only 3 of them
> contain
> > features inside of current Filter).
> 
> Eeek, getCount() on a big table can take tens of seconds (if you have
> millions of records).
> 
> > Did not investigate deeply but there
> > should be a preference to switch off this getCount() call from renderer
> in
> > case no features were loaded during usual request.
> > Isn't it the GT renderer calls this stuff, not UDIG wrappers ?... do not
> > remember exactly, but anyway - it would be good optimization to switch
> off
> > this call.
> 
> I could not find any getCount call in StreamingRenderer. Then I put a
> breakpoint in JDBCFEatureSource.count(xxx,xxx) and issued a GetMap
> request in GeoServer and the breakpoint was never reached, so I believe
> there is nothing in StreamingRenderer asking for row count (all counting
> code I know of in the end delegates to FeatoureSource.getCount(xxx)).
> I would suggest you do the same with uDig and your datastore and see
> what code triggers this call. I'm curious, me too.
> 
> Cheers
> Andrea
> 
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