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

[jankarin at post1.dknet.dk]

Hmm, Could you please tell me:

1. What hardware are you using?
2. How to "thin out the data"?
2. We'ere always only showing one layer at a time (one shape-file to be exact). Would the "throwing the shapes into PG/PostGIS"-thing have any effect then??

Thanks, Jan




"Arnulf Christl \\(CCGIS\\)" <arnulf.christl at ccgis.de> wrote:
> 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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