[OSM-dev] tiles at home disk usage

Frederik Ramm frederik at remote.org
Wed May 2 16:46:59 BST 2007


Hi,

> I also think we should avoid the DB and just keep a flatfile on disk.
> There's no way a database going to compete against an open/read 8
> bytes/close.

I agree that it is going to be faster. But the maintenance  
difficulties are scaring.

>> I think we don't need to store information of zoom17 sea tiles in the
>> middle of the oceans, so we should probably only store information up
>> to level 12 and only store higher zoom sea tiles near land.
>
> But if someone zooms in to level-17 in the middle of the ocean, they
> should still see blue. You're surely not proposing that the DB check
> level-17, then 16, then 15 all the way to level 12 until it gets a
> hit?

I think that "slightly lower performance for people viewing level-17  
tiles in the middle of the ocean" would be acceptable. (You could  
still do one query that goes like ... where (x=1000 and y=1000 and  
level=17) or (x=500 and y=500 and level=16) or (x=250 and y=250 and  
level=15) ... if you fear that mutliple queries are too inefficient.)

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'






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