[OSM-dev] mod_tile performance enhancements?

Frederik Ramm frederik at remote.org
Thu Jan 12 14:56:14 GMT 2012


Hi,

On 01/12/12 14:32, Jason Lee wrote:
> I am focusing and playing around with the METATILE parameter and get
> performance of 1 tile request :-
>
> METATILE(16) - 10 secs
> METATILE(8) - 3.5 secs
> METATILE(4) - 1.5 secs
> METATILE(2) - 0.6 secs

Maybe you are misunderstanding what this means. This means effectively

METATILE(16) - 10 secs - 256 tiles - 0.039 sec per tile
METATILE(8) - 3.5 secs -  64 tiles - 0.054 sec per tile
METATILE(4) - 1.5 secs -  16 tiles - 0.094 sec per tile
METATILE(2) - 0.6 secs -   4 tiles - 0.150 sec per tile

> So it seems the best performance for rendering a NEW TILE is to use the
> minimum metatile size of 2 (default is 8).

This is true if you want to render *one tile only*. If however you have 
an user behind an OpenLayers client who is likely to requires several 
neighbouring tiles, or if you intend to render a large area anyway, then 
the larger METATILE numbers give you much better performance.

Bye
Frederik



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