[OSM-dev] MySQL on dev

Frederik Ramm frederik at remote.org
Wed May 16 14:45:44 BST 2007


    may I suggest to move this discussion over to the new tiles at home  
list (CC'ing dev for one last time with this).

> It would probably be much quicker to use update, then check the row
> affected count (to make sure it worked), then insert if necessary.

Especially as the update will only fail when a certain is created for  
the very first time, whereas the majority will actually be re- 
renderings of existing tiles.

> This would still require doing it one at a time, though. Another  
> improvement
> would be to use prepared queries.

This would require switching over from the standard PHP mysql binding  
to mysqli. But I agree, a substantial performance increase could be  
gained especially as the same query is executed hundreds or even  
thousands of times.

> Of course, thinking laterally, if we can be sure that a whole level 12
> area will always be rendered by the same person on all zoom levels
> below, why do we store that information at all? We should just  
> store the
> level 12 data and calculate the rest only when it is asked for.

I have proposed similar reasoning for the land/sea tile detection -  
if you know that a particular level-8 tile is a land or sea tile,  
then you do not have to store this information for higher zoom levels.


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

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