[Maps-l] Tile expiry, a new attempt

[Kai Krueger]

On 01/02/2012 01:57 PM, Tim Alder wrote:
> Hello,
> please have in mind that we take the osm-labels-lang styles in  
> wikipedia only for zoom 0-6. For the more interesting zoom-levels we  
> take only default style for performance reasons. The only exeption is  
> the small hsb.wp ("Obersorbisch").

Interesting.

At least according to my local proxy logs, it loads the language tiles
in the german wikipedia at z15 as well.

I am not sure if it only displays the default style, but it is loading
the other ones, too.

It first loads tiles for "osm-no-labels" then "osm-labels-de" and
finally "default". I have seen that for all of the different coordinate
types, some of which load at z11, some at z13 and some at z15.


> 
> People from ru.wp ask me to support russian but I did affraid that it  
> will be too much load for us. But now is russian map so popular that  
> it is perhaps usefull, we should use pre-rendering for it.

Is the load really that much? The maps displayed in wikipedia are fairly
small and (spatially) localized around where the articles are. So that
is probably only a small subset of tiles that would be needed for a
general purpose slippy map.

Perhaps it would be good to analyze the apache logs and check the
referrers and user-agent to see how much traffic really comes from which
wikipedia, and how much comes from other sites like hikebikemap.de or
from e.g. smartphone apps using the toolserver as a source for tiles.

Kai

> 
> |Kay: Please excuse my ignorance, but what is "default"? Is it the same as
> |"osm"?
> Yes.
> 
> Greetings Kolossos
> 
> 
> Zitat von Kai Krueger <kakrueger at gmail.com>:
> 
>> Hello everyone,
>>
>> Over the past month, the server has been busy trying to re-render all of
>> the tiles to try to ensure more up-to date maps. This process is more or
>> less complete now and all of the map tiles should then be at least from
>> the 1st of December 2011.
>>
>> As one month old tiles is still not overly satisfying, I am now trying
>> to re-activate diff based tile expiry again.
>>
>> The full expiry of all styles remains infeasible for the moment and so I
>> am trying to introduce expiry slowly to see how far it can be pushed.
>>
>> As a start, I have activated tile expiry only for the highest zoom
>> levels (z15 - z18) and then only for the styles that currently are
>> embedded in one of the wikipedias.
>>
>> As far as I can tell these are the following styles:
>>
>> osm-no-labels osm-labels-de osm-labels-ca osm-labels-bg osm-labels-da
>> osm-labels-el osm-labels-es osm-labels-fa osm-labels-fr osm-labels-it
>> osm-labels-lv osm-labels-nl osm-labels-no osm-labels-pl osm-labels-ru
>> germany default hikebike
>>
>> If anyone knows of a language that I have forgotten, please let me know
>> and I will include it as well.
>>
>> So far, it looks like the server can cope with this, although I have
>> only activated it earlier today. Should it remain this way, I will try
>> and expand the zoom levels.
>>
>> As it is critical to reduce the number of low zoom tiles rendered, as
>> those still kill performance, lower zoom tiles will probably not be
>> expired as frequently. E.g. perhaps Z14 - Z11 on a daily basis, below
>> that even only in the background.
>>
>> We will have to see, though, how performance behaves over time.
>>
>> Happy new year,
>>
>> Kai
>>
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>>
> 
> 
> 
> 
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