[OSM-talk] Mapnik Tilecache Memory Error (Myanmar Cyclone Relief)

[Tom Hughes]

In message <1213039275.14294.15.camel at localhost.localdomain>
        Jon Burgess <jburgess777 at googlemail.com> wrote:

> The recent Mapnik builds try to mmap() the shapefiles while
> rendering[1]. Since the largest shapefile is a few hundred MB this could
> easily cause some issues if the file was mmap'd multiple times in a
> single process. This might be a particular problem if you use a 32-bit
> system in the multi-threaded Apache worker mode.

Um... no. At least not if it does the sensible thing and maps it
for shared read. Then it will only exist once in memory not matter
how many times a process maps it, or indeed how many processes map
it in.

In fact that is probably the ideal way to access a file like that
as you effectively have one disk backed cache of the file that is
shared by all users of it.

Tom

-- 
Tom Hughes (tom at compton.nu)
http://www.compton.nu/