[mapserver-users] mapcache

[Stephen Woodbridge]

On 6/6/2012 3:14 AM, Özgür Arslan wrote:
> Hi Everyone,
>
> Can someone explain me functions of the mapcache? Is it making my map
> fast or is it for another purpose. I read a lot about it I couldn't
> understand. what is the main work that mapcache does?

Mapcache is a proxy between mapserver or other services and you client. 
It takes the clients requests for tiles and gets them from the backend 
services and stores them in a cache then gives them to your client. If 
the requested tile is already in the cache then it just serves that.

So by using potentially a lot of disk space to save tiles in it avoids 
excessive drawing of the same tiles multiple times by the backend. This 
is basically how Google does it and why Google is so fast.


mapserver  <----> mapcache <-----> browser client
   |                 |
GIS data           tiles

If mapcache has the tile it servers it.
If mapcache doesnot have the tile it gets it from mapserver.

Serving tiles is fast, drawing tiles/images is slow. Mapcache can do 
some other tricks like compositing a larger image from a bunch of tiles 
to server WMS request faster also.

-Steve W