[Geoserver-devel] [Geotools-devel] Streaming renderer: memory preloading considered harmful

Hi all,
me and Andrea discussed a bit about where to do this indexing/caching
of features.
While in the mid-long run the best place would be at datastore level
for the moment it would be interesting to make this hack work inside
the renderer just to show the real potential.
If I recall correctly (my short-term memory is equal to zero lately..)
we were talking about datastore's wrappers/adapters able to do caching
and using notification mechanisms. This is as I said an experimental
idea up to now.

Anyway, as far as talking about improvements on renderer, go ahead
andrea, drop a few lines about your idea, let's discuss it a bit and
then implement it. I am sure Alessio will be happy to give a hand (he
knows about features more than I do) and I will be happy to provide
some help too.
My idea is to make this work on our branch of geoserver just to test
it extensively.

Keep up the good work.
Simone.

On 8/5/06, Andrea Aime <andrea.aime@anonymised.com> wrote:

Hi all,
as you may know, feature preloading in memory gives the streaming
renderer the ability to
pre-load the features into a spatially indexed FeatureResults instance.
This speeds up visibly the rendering process, but there is a catch: it
does not work :slight_smile:

Let me elaborate: memory preloading was a quick hack I made on a branch
1.5 years ago
to check various options to speed up rendering. One was memory
preloading, but I enabled
it only for one layer.
Right, you read it properly: it works only for one layer. If you add
more layers to the
map, they won't show up.
Unfortunately someone ported this hack onto the trunk and 2.2.x branches
without
noting the limitation.

For anybody using the 2.2.0 release, if you need speedier rendering
please either do:
- use the shapefile renderer;
- preload features into the memory data store and then use it (it won't
be as fast as
  the spatially indexed hack, but faster than loading from disk for sure).

Cheers
Andrea Aime

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Eng. Simone Giannecchini
President /CEO GeoSolutions

http://www.geo-solutions.it

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