impact of user concurrency in commonly used ogc map server implementations
DESCRIPTION
Masó, J., Díaz, P., Pons, X., Monteagudo, J.L., Serra, J., Aulí, F., (2011). Impact of user concurrency in commonly used OGC map server implementations, en: Proceedings of INFOCOMP. Barcelona, October 2011. ISBN: 978-1-61208-161-8.TRANSCRIPT
INFOCOMP 2011
Impact of User Concurrency in Commonly
Used OGC Map Server Implementations
INFOCOMP 2011October 2011
Used OGC Map Server ImplementationsJoan Masó, Paula Díaz, Xavier Pons, José L. Monteagudo-Pereira,
Joan Serra-Sagristà, Francesc Aulí-Llinàs
Center of Research in Ecology and Forestry Applications
Universitat Autònoma de Barcelona
Introduction
INFOCOMP 2011October 2011
Introduction
Three Steps for Disaster Management
INFOCOMP 2011October 2011
GEO-PICTURES is an EC FP7 SPACE project with the aim of
integrating satellite imagery with in-situ sensors and geo-tagged images as a tool for decision making in emergency crisis
Rapid Mapping and Technology
INFOCOMP 2011October 2011
The images
� 22 satellite images of GeoEye-1 (Orthorectified GeoTIFF; provided by Google)
� (http://www.google.com/relief/haitiearthquake/geoeye.html)
� Covering Port-au-Prince
INFOCOMP 2011October 2011
� Covering Port-au-Prince and surroundings
� 16-01-2010, 3 days after the Earthquake
� Each image has 196 373 kb � 4.21 Gb
� 40 994x57 392 pixels
pdiaz4
Diapositiva 5
pdiaz4 Al Web de descàrrega posa:
By downloading these files, you agree to use the imagery solely for non-commercial use related to emergency relief, and to provide a proper and distinct photo credit to “GeoEye Satellite Image.”
Això significa que hem de posar el logo de GeoEye a la presentació?pdiaz; 13/10/2010
The service
� We are going to test implementations of two standards:
� Web Map Service (WMS) standard
INFOCOMP 2011October 2011
� Web Map Tile Service (WMTS) standard
� Both standards are Open Geospatial Consortium standards
� Assess performance
Web Map Service
INFOCOMP 2011October 2011
This is a map
Web Map Tile Service
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This is a tile
INFOCOMP 2011October 2011
Methodology
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Methodology
The analysisServers ClientsStandardsData
Web Map Service
(WMS)
Web Map Service
INFOCOMP 2011October 2011
Web Map Service
Cache (WMS-C)
Tile Map Service
(TMS)
Tile Map Tile Service (WMTS)
Traditional WMS server-client interaction
WMSServer
request GetMap
URL
INFOCOMP 2011October 2011
response
� All studied protocols request maps by creating an URL with specific syntax� http://www.ogc.uab.es/cgi-bin/SIGMA/MiraMon5_0.cgi?VERSION=1.1.0&
REQUEST=GetMap&SRS=EPSG:27573&BBOX=532776,22819,538776,26419&WIDTH=600&HEIGHT=360&LAYERS=mh-andorra&STYLES=&FORMAT=image/gif&TRANSPARENT=TRUE
� URL requests were randomly generated and sent from different clients
� The time response is stored in logs and latter analyzed
Results
INFOCOMP 2011October 2011
Results
Evaluation of WMS Concurrent Requests to a Single Server
WMSServer
reqGetMap
INFOCOMP 2011October 2011
WMS Server Server
res
Evaluation of WMS Concurrent Requests to a Single Server
�More than one hundred different requests were done (without optimizing speed configurations).
�The influence of the pixel size and the image size in
INFOCOMP 2011October 2011
�The influence of the pixel size and the image size in the time response were evaluated
�The requests were made from up to 5 concurrentclients.
�The time response for the requests are exposed in graphs.
Evaluation of WMS Concurrent Requests to a Single ServerResponse time of 5 different server vendors at different scales (pixel sizes) each one under
5 simultaneous requests
10.000
MapServer
GeoServerMiraMon Server
ArcGIS Server Express Server
INFOCOMP 2011October 2011
0.010
0.100
1.000
0.0001 0.0010 0.0100 0.1000 1.0000 10.0000 100.0000
Pixel Size (seconds of arc)
Tim
e (s
econ
ds)
Evaluation of a Cluster of Servers
�To overcome the performance degradation in
concurrent requests a possible solution is to set up a
cluster of servers
INFOCOMP 2011October 2011
cluster of servers
�The cluster of servers act as a virtual single server
� 6 computers are able to respond at same time to different
clients as if they were like a faster single server
Evaluation of a Cluster of ServersEvaluation of the response time for Pixel Size (Clients to MiraMon Single Server)
60.0
80.0
100.0
120.0
140.0
160.0
180.0
Tim
e (m
illis
econ
ds)
17 clients
14 Clients
11 Clients
8 Clients
4 Clients
1 Client
INFOCOMP 2011October 2011
Evaluation of the response time for Pixel Size (Clients to MiraMon Server Cluster)
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
0.0000 2.0000 4.0000 6.0000 8.0000 10.0000 12.0000 14.0000 16.0000
Pixel Size (seconds of arc)
Tim
e (m
illis
econ
ds)
17 clients
14 Clients
11 Clients
8 Clients
4 Clients
1 Client
0.0
20.0
40.0
0.0000 2.0000 4.0000 6.0000 8.0000 10.0000 12.0000 14.0000 16.0000
Pixel Size (seconds of arc)
Tiling the Request and the Response: Sequential
WMSServer
reqGetMap
reqGetMap
reqGetMap
reqGetMap
reqGetMap
INFOCOMP 2011October 2011
Server
Tiling the Request and the Response
� Some WMS clients are able to tile the space in a regular matrix of small pieces.
� They need several tiles to cover the whole viewport
� They can recycle some tiles when the user moves the view laterally
INFOCOMP 2011October 2011
They can recycle some tiles when the user moves the view laterally
� Also can take advantage of the cache mechanisms
� If the caching mechanism cannot help the response time can increase even if each tile is smaller that the whole view
� Tiled clients (tiles of 256x256 pixels) were simulated in three configurations.
Tiling the Request and the Response: Sequential�Results of the WMTS speed metrics
Time response for sequential 256x256 tiled requests on a pure WMS server
10MapServerGeoServerTilecache
INFOCOMP 2011October 2011
0.01
0.1
1
0.000
90.0
010
0.002
40.0
029
0.005
10.0
076
0.010
20.0
145
0.018
80.0
246
0.033
10.0
462
0.185
50.2
130
0.265
40.4
717
0.567
01.0
383
1.642
5
seconds of arc
Sec
on
ds
(tim
e)
TilecacheMMServerArcGIS ServerExpress ServerGeoWebCache
Sequential tiled WMS
Tiling the Request and the Response: Concurrent
WMSServer
reqGetMap 1reqGetMap 2reqGetMap 3reqGetMap 4reqGetMap 5
INFOCOMP 2011October 2011
Server
Tiling the Request and the Response:Concurrent�Results of the WMTS speed metrics
Time response for sequential 256x256 tiled requests on a pure WMS server
10MapServerGeoServerTilecache
Time response for unlimited concurrent 256x256 tiled requests on a pure WMS server
10MapServer
INFOCOMP 2011October 2011
0.01
0.1
1
0.000
90.0
010
0.002
40.0
029
0.005
10.0
076
0.010
20.0
145
0.018
80.0
246
0.033
10.0
462
0.185
50.2
130
0.265
40.4
717
0.567
01.0
383
1.642
5
seconds of arc
Sec
on
ds
(tim
e)
TilecacheMMServerArcGIS ServerExpress ServerGeoWebCache
Sequential tiled WMSConcurrent Tiled WMS
0.01
0.1
1
10
0.00
090.
0011
0.00
270.
0049
0.00
760.
0110
0.01
590.
0245
0.03
310.
0627
0.19
150.
2348
0.47
170.
5745
1.17
30
seconds of arc
Sec
on
ds
(tim
e)
GeoServerTilecacheMMServerArcGIS ServerExpress ServerGeoWebCache
Tiling the Request and the Response: Semi-concurrent
�Results of the WMTS speed metrics
Time response for sequential 256x256 tiled requests on a pure WMS server
10MapServerGeoServerTilecache
Time response for unlimited concurrent 256x256 tiled requests on a pure WMS server
10MapServer
Time response for up to 4 concurrent 256x256 tiled requests on a pure WMS server
INFOCOMP 2011October 2011
0.01
0.1
1
0.000
90.0
010
0.002
40.0
029
0.005
10.0
076
0.010
20.0
145
0.018
80.0
246
0.033
10.0
462
0.185
50.2
130
0.265
40.4
717
0.567
01.0
383
1.642
5
seconds of arc
Sec
on
ds
(tim
e)
TilecacheMMServerArcGIS ServerExpress ServerGeoWebCache
Sequential tiled WMSConcurrent Tiled WMS
0.01
0.1
1
10
0.00
090.
0011
0.00
270.
0049
0.00
760.
0110
0.01
590.
0245
0.03
310.
0627
0.19
150.
2348
0.47
170.
5745
1.17
30
seconds of arc
Sec
on
ds
(tim
e)
GeoServerTilecacheMMServerArcGIS ServerExpress ServerGeoWebCache
Semi-concurrent Tiled WMS
0.01
0.1
1
10
0.00
090.
0011
0.00
270.
0049
0.00
760.
0110
0.01
590.
0245
0.03
310.
0627
0.19
150.
2348
0.47
170.
5745
1.17
30
seconds of arc
Sec
on
ds
(tim
e)
MapServerGeoServerTilecacheMMServerArcGIS ServerExpress ServerGeoWebCache
Conclusions (1/2)
� The work presented covers:
� A metrics on WMS and WMTS services
� GeoServer, MapServer, MiraMon Map Server, ArcGIS Server, Express Server
� TileCache GeoWebCache
� A set of recommendations of Disaster Management
Easy to setup: MapServer
INFOCOMP 2011October 2011
� Easy to setup: MapServer
� Easiest configure and update: GeoServer
� Fastest: Express Server
� The speed tests described are a practical demonstration of the suitability of certain servers and service configurations in certain domains where reliability of services is imperative
� We have seen differences in performance of 2 order of magnitude.
� All the analyzed servers have slower performances when the number of simultaneous clients is increased
� A cluster of server dramatically improves performance
p2
Diapositiva 25
p2 HE FET DUES OPCIONS PER A LA DIAPO 1/2 DE CONCLUSIONS, UNA MÉS DENSA I L'ALTR AMOOLT MÉS LLEUGERA. TAMBÉ POTS COMBINAR LA LLEUGERA 1/2 AMB LA 2/2 QUE TROB QUE ÉS DENSA PERÒ QUE ÉS LA QUE VAREM FER A VENÈCIA. p.diaz; 25/10/2011
Conclusions (2/2)� In order to improve performance, some clients request tiles to servers that are not
prepared to serve them
� This results on no better performance in some servers
� Server optimization for tile requests is needed.
� Web clients auto-impose themselves a limit in the number of parallel request
INFOCOMP 2011October 2011
� Web clients auto-impose themselves a limit in the number of parallel request
� We saw that this more conservative strategy results on better performance
� MapServer and GeoServer with common open source services that do not require any data preparation process but
� their performance is worst than other services that require indexing methods like MiraMon Map Server
� MapServer (based on C++ code) performs better than GeoServer (based on Java code) under single client requests, but GeoServer is surprisingly faster under concurrent simultaneous requests.