[OSM-dev] [OSM-talk] donating read-only api-mirrors

Stefan de Konink stefan at konink.de
Fri Feb 6 15:48:59 GMT 2009


Tom Hughes wrote:
> Erik Johansson wrote:
> 
>> How much of the DB load comes from the read only part of the  API, and
>> what if you remove the area limit on the map call?
> 
> If I remove the area limit then somebody will do a massive query that 
> will suck up all the memory on the machine and everything will die.
> 
> That limit is not (primarily) about the cost of gathering the required 
> data, though obviously that might become an issue as well, it's about 
> the fact that we are holding the whole result set in memory (several 
> times over in fact) on the rails server and those servers only have a 
> finite amount of memory.

In that case; it seems to get more valid for lookup to switch to a slave 
server that doesn't. The generation of XML is only a translation task of 
SQL, and even that can be done streaming :)


Stefan




More information about the dev mailing list