[OSM-dev] OSM Architecture

Frederik Ramm frederik at remote.org
Fri May 14 20:34:11 BST 2010


Calin Juravle wrote:
> If you have time, can you point me to a bottleneck you encountered?
> (maybe it was discuss on some thread here).

One example of the procedure that Tom mentioned is the introduction of a 
"tile" field in our MySQL data model which allowed us to bypass the 
limitation that MySQL didn't have two-dimensional indexes and thus it 
was rather expensive to search for all objects in a certain goegraphic 
rectangle. This was not a problem when OSM still had little data and few 
users, and became more of a problem as the data grew. The idea had been 
mentioned every now and again, but in the end Tom just sat down and 
implemented it in the way he thought would work (I'm sure he'll be able 
to elaborate on details). It was not really a community process, and it 
seldom is.

> My hope was to get some hints about the tradeoff points in OSM, and
> some examples when, during development, a certain quality aspect was
> prioritize over the others. But I understand that these may be hard to
> isolate.

Maybe we should do it the other way round; you explain what you're up 
to, and then we can see if we can help you.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

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