[OSM-dev] mod_tile performance enhancements?

Jason Lee jaslee.st at gmail.com
Thu Jan 12 10:03:33 GMT 2012


Thanks for the tip Frederik,
I enabled Postgres logging and the SQL selects are quite fast (under
1000ms). I am guessing the load maybe on the tile rendering and tile
cutting maybe.

On Wed, Jan 11, 2012 at 11:43 AM, Frederik Ramm <frederik at remote.org> wrote:

> 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"
>
>
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