I don't know of any. Optimizing the map server configuration is could
be the wrong way of going about solving your problem
Look into optimizing your database. Sure there are indexes; but are
they being used? "explain" can help you determine that
(ie
http://www.redhat.com/docs/manuals/database/RHDB-7.1.3-Manual/sql/sql-explain.html)
- Are there joins or subqueries going on "under the hood"? Joins are an
expensive operation whether there is an index or no index.
- Perhaps an expensive trigger is getting fired for every select?
- etc.
Ed is right, "The amount of geometry involved is so small, the
bottleneck has to be the raster processing" -- is a bad assumption.
Retrieving a small amount of data from a large table will take while
(indexes help). Performing a join takes even longer.
Explain will explain.
Stephen Davies wrote:
G'day all.
Does anybody have a howto on Mapserver performance enhancement?
My particular environment of interest is a relatively small set of
geometries in a PostGIS database and a collection of geotiff aerial
photography images onto which I overlay the geometries.
The geometries are fully indexed, relatively static and vacuum analyzed
every night.
One of the options that users have is to request a "movie" of up to 20
frames; each of which consists of a background raster plus up to about
five circular geometries, about five points and maybe ten other
lines/polygons.
The amount of geometry involved is so small, the bottleneck has to be
the raster processing. The images are 2m/pixel and are typically 20 -
150 Mb each. The frame extents include most if not all of an image so
tiling does not seem relevant.
I have specified 80% JPEG as the output to minimise final image size and
this seems successful (at least in terms of size and hence download
time)
I am looking for ways to reduce the time taken in the image generation
phase.
TIA,
Stephen Davies
========================================================================
This email is for the person(s) identified above, and is confidential to
the sender and the person(s). No one else is authorised to use or
disseminate this email or its contents.
Stephen Davies Consulting Voice: 08-8177 1595
Adelaide, South Australia. Fax: 08-8177 0133
Computing & Network solutions. Mobile:0403 0405 83
--
Clint Johnson
Refractions Research Inc.
[EMAIL PROTECTED]
