[OSM-dev] mod_tile performance enhancements?

[Frederik Ramm]

Hi,

On 01/11/2012 11:39 AM, Jason Lee wrote:
> Ten seconds does sound quite slow and I was wondering what can be done
> to improve it. Just out of curiosity, I tried disabling all the 7 Layers
> except for 1 Layer in the Mapnik stylesheet, so the rendering requires a
> lot less db querying and map rendering

To get a definitve answer on how much time is spent in database 
processing, set log_min_duration_statement to 0 (default is -1 = 
disabled) in your postgresql.conf, kill -HUP the database, and re-run 
your request. You'll get durations for every single statement. It is 
very easy to overlook a performance killer here. If you find a statement 
that takes seconds, run an "explain" on it to make sure it uses an 
index, or create an appropriate index if it doesn't.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"