Re: [Geoserver-users] Poor Throughput

[David R. <da...@ru...>]

Gabriel:

A hill-shade raster layer is a map layer showing the topography of the land by shading the sides of all the hills.

I think it usually (if not always) uses a DEM (digital elevation model) to artificially generate the appearance of light coming in from one direction, so slopes facing towards the light are lighter, and slopes facing away are darker.  There must be another name for it.... it's a very common technique.

Here's a link to an example: http://maps.unomaha.edu/atlas2002/pages/06-Hillshade.pdf

Hillshade is the brown background.

If anyone could give me some information on creating such a layer for use in geoserver, I'd appreciate it.

David

Gabriel Roldan wrote:
> Btw, David, what's an "hill-shade raster layer"?
> 
> Is it a raster layer you have on your ArcSDE instance? if so, did you
> try configuring it on geoserver? With the latest development on support
> for ArcSDE rasters it should sort of rock too, but I'd certainly love
> some feedback on how it behaves under load.
> 
> 
> Cheers,
> Gabriel
> 
> David Rush wrote:
>> Gabriel:
>>
>> I tried replacing the gt-arcsde-2.5.5.jar with
>> gt-arcsde-2.5-SNAPSHOT.jar from your link.
>>
>> Wow.
>>
>> Isolated requests are now responding in about 0.26 seconds, a nearly
>> ten-fold improvement.
>>
>> Sending a new request every 1000 ms for 30 seconds got an average
>> response time of 0.245 sec.
>> 500 ms for 30 sec average 0.233 sec.
>> 200 ms for 30 sec avg 0.322 sec.
>> 100 ms for 30 sec avg 1.987 sec.
>> 50 ms for 30 sec avg 2.170 sec.
>>
>> I tried a 20 ms rate, but my tool cratered at that rate.
>>
>> The faster rates also started showing significant CPU load (40%-ish)
>> on the geoserver machine, which is a good sign.
>>
>> At present I have the min/max poolConnnections at 10/10.  Earlier I
>> had it at the default of 2/10, and didn't notice a big diff when I
>> switched it to 10/10.
>>
>> Thanks!  This is looking a lot more promising.
>>
>> David
>>
>> Gabriel Roldan wrote:
>>> Hi David,
>>>
>>> sad to hear that. Yet, as you know perf tunning is a complicated matter.
>>> The following are the factors I can think off the top of my head that
>>> you may need to double check:
>>> - Did you assess the impact of the number of available ArcSDE
>>> connections to GeoServer? (you can change the pool.maxConnections
>>> parameter on the DataStore's edit page)
>>> - Do the layers have proper spatial indexes? do they have indexes on the
>>>  non spatial attributes used by your SLD, if any?
>>> - You said ArcGIS Server is performing well so the question of if you
>>> compared with other products does not apply. But my main suspect here is
>>> the number of connections. Did you check how many connections does
>>> ArcGIS Server use to serve your requests, and how they relate to the
>>> ones GeoServer is allowed to use?
>>>
>>> If you wish I would be glad of setting up an environment similar to
>>> yours (can you share an sdeexport of your 4 polygon layers with me?) and
>>> do some profiling. I'm very interested on helping you with this cause my
>>> latest perf chek on the plugin was getting better results than the
>>> postgis one, but that may have changed over my feet.
>>>
>>> Ah... btw, I just fixed a scalability issue that's surely related to
>>> this. Check this out: http://jira.codehaus.org/browse/GEOT-1956
>>> The fix is for geotools 2.5.6 and GeoServer 1.7.5, so you may want to
>>> try out the latest nightly with the fix applied:
>>>
>>> <http://gridlock.openplans.org/geoserver/1.7.x/geoserver-1.7.x-latest-war.zip>
>>>
>>>
>>> and
>>> <http://gridlock.openplans.org/geoserver/1.7.x/ext-latest/geoserver-1.7.5-SNAPSHOT-arcsde-plugin.zip>
>>>
>>>
>>>
>>> Let me know how it goes.
>>>
>>> Cheers,
>>> Gabriel
>>>
>>> David Rush wrote:
>>>> I've been experimenting with GeoServer 1.7.4 as a possible alternative
>>>> to an expensive, proprietary product.
>>>>
>>>> I've set up a WMS service with 4 polygon layers inside it, nothing
>>>> particularly complicated and simple rendering.  Data is served from
>>>> (DataStore) ArcSDE, with the feature classes in the web mercator
>>>> projection.  I making requests for EPSG:900913.  I'm trying to get the
>>>> source projection and requested projection to be the same to avoid
>>>> reprojecting on-the-fly, but I'm not sure that I'm succeeding at that.
>>>>
>>>> I'm using Tomcat 6.0 and JDK 1.6 on a four-processor, 2.5 GHz Windows
>>>> Server 2003 box with 4 GB RAM.
>>>>
>>>> Single, isolated WMS requests to this service have a response time of
>>>> about 2.5 seconds.  That's a little slow, but our real concern is
>>>> throughput - being able to handle a high load of simultaneous requests.
>>>>
>>>> To measure that, I have a home-grown multi-threaded application that
>>>> can throw multiple requests at a map service, at whatever rate I want,
>>>> and report the response times.
>>>>
>>>> When I throw a new request at my WMS service on GeoServer every 3000
>>>> milliseconds for 30 seconds, the average response time is 2.5 seconds.
>>>>
>>>> When I throw a new request every 2400 ms for 30 seconds, the average
>>>> response time is 4.6 seconds.
>>>>
>>>> When I throw a new request every 1000 ms for 30 seconds, the average
>>>> response time is 31.9 seconds.  The response rate does not "ramp up"
>>>> slowly... it pretty quickly gets to responses in the 30 second range,
>>>> and stays up there.
>>>>
>>>> Clearly it's not scaling well.  Even when hitting it "hard" like in
>>>> the above test, the CPUs on the server are showing very low
>>>> utilization (can hardly tell there's anything special going on).
>>>>
>>>> I've tried many of the suggestions in
>>>> http://geoserver.org/display/GEOSDOC/2.6+GeoServer+in+Production+Environment
>>>>
>>>> but haven't seen any significant benefit.
>>>>
>>>> For comparison, an ArcGIS Server map service on the same machine with
>>>> the same layers using the same ArcSDE data sources (plus some labels
>>>> and a hill-shade raster layer that the similar GeoServer WMS service
>>>> doesn't have) gives an average response time of 1.1 seconds when I
>>>> throw a new request at it every 1000 ms for 30 seconds.
>>>>
>>>> When I throw a new request at ArcGIS Server every 500 ms for 30
>>>> seconds, the average response time is 1.2 seconds.
>>>>
>>>> And I know there's some throughput tuning on ArcGIS Server that will
>>>> improve throughput that I have not yet done.
>>>>
>>>> So, any suggestions for getting better throughput and scaling out of
>>>> GeoServer?
>>>>
>>>> David
>>>>
>>>>
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