[Tilesathome] lowzoom rendering takes forever?

[Christopher Schmidt]

On Sat, Nov 24, 2007 at 12:18:57PM +1100, Brent Easton wrote:
> 
> 
> *********** REPLY SEPARATOR  ***********
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> On 23/11/2007 at 7:50 PM Christopher Schmidt  wrote:
> 
> >On Fri, Nov 23, 2007 at 11:21:08PM +0100, Thomas Stets wrote:
> >>  [#33   0% jobinit] Doing tileset 146,99 (zoom 8) (area around
> >> 37.158240,26.015625)
> >>  [#33   0% lowzoom] Rendering...
> >>
> >> It seems that the client is trying to do a lowzoom rendering, but its
> >> been sitting at 0% for several hours now.
> >> It still takes up one CPU (of my dual G5 Mac).
> >
> >Okay, this seems to be a serious problem. Since the enabling of lowzoom
> >requests being handed out to clients, we've seen a significant downturn
> >in the number of bytes being uploaded to the server, and a lot more
> >tiles end up not completing in the 1.5 hours, and re-requested.
> >
> >I can't comment on exactly why this is, but I can comment that I'm
> >seeing xmlstarlet taking minutes -- up to 10 -- to transform a single
> >lvl 8 dataset. Tileset 126,83 (zoom 8) is currently on its 15th minute
> >of renering, and it's only on 'Transforming zoom level 9'. (Now 22
> >minutes in, and transforming level 10.)
> >
> >I don't know anything about the client, but *something* isn't right
> >here, and it might make sense to figure out what.
> 
> I believe there is nothing wrong, that's just the way the new lowzoom works.
> The amount of data downloaded in a z8 tile can be huge for areas around well mapped cities.
> 
> In the case of 126,83 you are looking at a 20Mb osm file which is equivalent in complexity to a moderately complex  AND Netherlands tiles.

>From osmxapi, I'm getting it as 10.7MB, not 20MB. And the machine that
is running this can render the complex netherlands tiles in
approximately 1.5 hours. So far, I'm an hour in, and I'm still
transforming the data. 

Perhaps I just want something that I can't have :) But I think it
probably makes more sense to fall back to a stitching type lowzoom
render if the data from osmxapi is too large. Cause this is somewhat
silly :)  

Regards,
-- 
Christopher Schmidt
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