[OSM-dev] C++ implementation of the API

Raphaël Jacquot sxpert at sxpert.org
Fri May 30 05:03:21 BST 2008


Joachim Zobel wrote:
> Am Montag, den 26.05.2008, 15:07 +0100 schrieb Tom Hughes:
>> The reason is that we have to allow about 600Mb or so for each call
>> and that quickly mounts up as you try and add extra simultaneous
>> accesses.
> 
> If _that_ amount of memory is needed this probably means the XML is
> build in memory. This could be done the SAX way instead.


considering how simple the xml is, it could probably be done the printf 
way, that sure would make it less memory abusive.
one thing that it may be doing, is getting *all results* in one go from 
the database server, instead of one result at a time, resulting in 
having the entire set of data in the web server's machine memory at some 
point.
requesting one row at a time *will* result in instant memory consumption 
cutoff and won't have any effet on the database server, which is much 
better at handling this sort of thing (it can handle the same row in ram 
for various requests at the same time)

> Sincerely,
> Joachim

raphael
(who now works on seismic data sets...)





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