Raster tile indexing in PostGIS

[Frank Warmerdam]

Thy, Kristian wrote:
> Frank et al,
>  
> First, your comments and thoughts are much appreciated. I am trying to 
> form a picture for the infrastructure we are going to build to serve a 
> high-performance WMS with fairly static data, so I guess shapefiles 
> sound more efficient than the database access. But one thing came to 
> mind while buying my groceries - how do shapefiles perform under 
> increasing load on the server? I.e. is it possible for several instances 
> of MapServer to read concurrently from the same shapefile and spatial 
> index, or will the database help on performance in this scenario? I know 
> it's dependent on the nature of my data and the number of concurrent 
> users, but if it's possible to give some sweeping comments on this issue 
> I'm very interested in hearing your opinions.

Kristian,

Generally speaking the shapefiles, and the spatial indexes will get cached
in RAM.  As long as your server has lots of ram, multiple concurrent access
should be no problem.  In this regard I think shapefiles will do at least
as well as an RDBMS given the same piece of hardware and RAM.  If you are
planning for very heavy use, don't skimp on RAM.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org