AW: Re: [Mapserver-users] Slow MapServer with large data

[Arnulf Christl CCGIS]

Hi,
15 sec does seem a lot, but maybe thats it. Our shapefile sizes usually do
not exceed 10 MB to prevent this happening. The problem is that shapes
physically are sequential files and performance must go down when the
filesize increases. Indexing (shptree.exe) and breaking up (tile4ms.exe)
really do help a lot, strange that you don't seem to notice the effect.
Maybe you try to always show the comletet extension of the shapefile, then
the mentioned tools will not be of much help. If that is the case I would
suggest that you set zooming limits by using MINSCALE and MAXSCALE to only
access the files when at an appropriate scale. For the overview you could
use a raster "screenshot" of the shapes (shp2img.exe) or thin out the data.
Then the performance issue should not be a problem anymore.
If you still cannot get enough performance you should consider throwing the
shapes into PG/PostGIS. If thats still not enough, separate the MapServer
software and the PostGreSQL DB to run on separate machines (hardware). This
will improove performance by factor 5 to 10 (thats our hands-on experience).
When you have reached this stage the map (from the same data) should be
delivered in about 1 or 2 seconds.

Cheers, Arnulf.

-----Ursprüngliche Nachricht-----
Von: mapserver-users-admin at lists.gis.umn.edu
[mailto:mapserver-users-admin at lists.gis.umn.edu]Im Auftrag von
jankarin at post1.dknet.dk
Gesendet: Dienstag, 13. Mai 2003 12:25
An: mapserver-users at lists.gis.umn.edu; woodbri at swoodbridge.com
Betreff: Re: Re: [Mapserver-users] Slow MapServer with large data


I have tried on af few shapefiles, but it doesn't help much. And it wouldn't
have any effect on our tab-data.

By the way: Is 15 sec. for a 25 MB shapefile/40 sec for a 30 MB MapInfo
map-file the usual speed for MapServer on a PIII, 650 Mhz, 262 MB RAM ?

If it is, there's only one thing to do,  if not .....
Anyone have some ideas?

Jan


woodbri at swoodbridge.com wrote:
> Have you built shptree indexes for all your shapefiles?
>
> On 9 May 2003 at 13:14, jankarin at post1.dknet.dk wrote:
>
> > Hello
> >
> > I have a little problem with the speed in MapServer.
> > We're trying to make qiuck-viewer to shape- and
> tab-formats, but
> > MapServer is running slow with large data: 20 seconds:
> Shapefil 17 MB,
> > dbf-fil 9,5 MB. 45 seconds: Map-fil 31 MB, Dat-fil 25 MB.
> >
> > I have been trying with the GCI-version and PHP Mapscript
> - same
> > result.
> >
> > I am running MapServer 3.6.4 with PNG-output under Apache
> 2.4.5 on
> > Windows 2000. The pc is Pentim III, 650 Mhz, 262 MB RAM.
> >
> > In another installation (PII, 400 Mhz, 196 MB RAM) a
> shapefile
> > (shapefile 17 MB, dbf-fil 9,5 MB) took 80 seconds to
> show.
> >
> > We're using MapServer in an application which is
> dynamically creating
> > map-files with Mapscript (only showing one layer at a
> time). We're
> > talknig about 17.000 layers in shape- and tabformats, so
> it is not
> > possible to improve indexfiles or anything else related to
> a single
> > layer.
> >
> > Can anyone help?
> >
> > Thanks,
> >
> > Jan Christiansen
> > jankarin at post1.dknet.dk
> > Engineering College of Copenhagen
> >
> > _______________________________________________
> > Mapserver-users mailing list
> > Mapserver-users at lists.gis.umn.edu
> > http://lists.gis.umn.edu/mailman/listinfo/mapserver-users
> >
>
>


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