On Tue, Jan 19, 2016 at 6:53 AM, Paul Wittle <p.wit...@dorsetcc.gov.uk>
wrote:
> The issue we have noticed is that that layer takes an age to draw tiles
> when they are not in the cache and we wondered how to speed it up. There is
> no issue from the Oracle point of view, we can query it and it returns
> reasonably quickly but the GeoServer is a different. The style is just a
> couple of coloured triangles based on property type so it is not complex.
>
>
I know that GeoServer can render the entire road network of Texas (a couple
of million roads) in like 40 seconds on a 5 years old computer, if the data
source manages to provide the data fast enough... and the rendering engine
is the same regardless of the data source.
Do your tiles contain millions, or hundred of thousands, points?
As an alternative, are you trying to render many very complex tiles in
parallel, and are running on Windows with the Oracle JDK? That has a known
scalability problem, which can only be addressed by replacing some parts of
the JDK, or running multiple instances of GeoServer in parallel:
http://www.geo-solutions.it/blog/developerss-corner-achieving-extreme-geoserver-scalability-with-the-new-marlin-vector-rasterizer/
If that's not the case, the issue is still likely to be searched in the
data source.
Unfortunately when the data source is Oracle things start getting south
quickly.... For example, you say the query you run is fast, but you may not
actually
be replicating the query made by GeoServer, whcih is using prepared
statements, while I assume when you run it by hand, you are proving
a full sql statement without params (without "?" in the place of the bbox
geometry to be clear).
The access plan that Oracle makes in those cases can be comically wrong...
wondering, are your index statistics up to date?
The Oracle documentation states that to get good performance one has to use
prepared statements, but I cannot say I ever managed
to get fast and Oracle in the same sentence (e.g.
http://www.oracle.com/technetwork/articles/vasiliev-oracle-jdbc-090470.html
)... thinking
out loud, maybe we should try to have an option for prepared and non
prepared statements in Oracle too, at least with the non prepared approach
one could actually run the very same query GeoServer builds.
That would be a significant effort though, Oracle XE cannot even read WKT
and one has to use its own silly native syntax, for which we
don't have a complete generator... not to mention proper date handling,
which would also be rather annoying to setup.
It's something that would definitely need resourcing (and might, or might
not, solve the issue, although if you say the manual query
is fast, then it might at least in your case):
https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer
Cheers
Andrea
--
==
GeoServer Professional Services from the experts! Visit
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==
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
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