[Mapserver-users] PostGIS / Shapefile Performance Question

[Lowther, David W]

John,

You are absolutely right. This is not fair to PostGIS. But my WWW server is
on Win32, and when I ran postgres/postgis under cygwin on a 700mhz 256mb ram
machine the performance was slower then on linux with 233mhx 128mb ram. I'm
stuck in the unfair until I move mapserver and the www server to linux.

Dave

-----Original Message-----
From: John Deck [mailto:jdeck at socrates.Berkeley.EDU]
Sent: Wednesday, January 15, 2003 11:58 AM
To: 'Lowther, David W'; mapserver-users at lists.gis.umn.edu
Subject: RE: [Mapserver-users] PostGIS / Shapefile Performance Question


To be fair to postgis you will want to make the comparison to shapefiles
with a local install of postgres/postgis only.  Having postgis reside on
a separate machine can drastically impede performance.

In my own experience shapefiles are a tad faster than postgis for
querying single polygons and drawing them.  However, I haven't delved
into tuning postgis/building spatial indexes and performed any advanced
queries either.  

John

> -----Original Message-----
> From: mapserver-users-admin at lists.gis.umn.edu [mailto:mapserver-users-
> admin at lists.gis.umn.edu] On Behalf Of Lowther, David W
> Sent: Wednesday, January 15, 2003 9:42 AM
> To: mapserver-users at lists.gis.umn.edu
> Subject: [Mapserver-users] PostGIS / Shapefile Performance Question
> 
> Hi List,
> 
> Has anybody experimented with drawing / query time of features from
> shapefiles vs. features from PostGIS?
> 
> My experience (and it is extremely limited) is as follows. This is why
I
> am
> asking about your experiences.
> 
> Drawing a layer based on a shapefile that is located on the same
physical
> drive as mapserver is faster then drawing that same layer from PostGIS
> running on a separate machine. But obviously this is a result of
several
> factors including the network connection (in this case 100 megabit on
both
> machines), the hardware in the Postgres server (in this case 233mhz,
128mb
> ram), and the traffic (in this case just what I am doing by testing).
> 
> Are there certain situations in which the access to PostGIS might be
> quicker
> then a shapefile, say when zoomed in closely or zoomed way out or when
> doing
> a point based query?
> 
> Is there a point where the number of features in a layer would cause
> PostGIS
> or shapefiles to perform better?
> 
> What if I put a monster of a machine in place as the postgres server?
> Could
> I build a postgres server that would be as fast as shapefiles local to
> mapserver?
> 
> What happens as the application scales? If I saw traffic like
mapquest.com
> or something would shapefiles be faster than PostGIS?
> 
> Sorry if this seems irrelevant or silly line of questions. I just have
a
> conflict between the convenience / queryability of PostGIS and the
speed
> of
> shapefiles.
> 
> Thanks,
> 
> Dave Lowther
> 
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