[Tilesathome] changetracker / flohoff-ct prio3 requests

[spaetz]

On Sat, Sep 06, 2008 at 08:37:06PM +0200, Florian Lohoff wrote:
> So the idea is to mix those two - so keep the clients busy with prio1/2
> queries and mix prio4 requests e.g. missing tiles into it up to the max
> of the queue.
> 
> The culprit i think i have identified is the changedtiles requests which
> seem to run every 6 hours. So we run like 3-4 hours with "pure" prio4 and
> 2 hours with prio2 queries.
> 
> The current idea is to queue changedtiles requests all the time e.g.
> every minute but only a few.

Interesting, and seems to make sense to me. However, we can solve this easily without a new script. i just have to run the changed Tiles script and smaller intervals, like once every 10 minutes for the previous 10 minutes or so. The only reason why I did not do this so far, is my theory that very complex tilesets (metropolis downtown) will be modified very often. A 10 minutes interval of London downtown would lead us to potentially send out rerender requests for those areas very often. Those tilesets often slow down te system, as they get handed around quite a bit until a renderer succeeds in rendering them.

And we do want the changed tiles to render as fast as we can, after all t at h is about quick turnaround times, so keeping them in the queue articifially will increase turn-around time.

mmh, not sure how this can be solved in the best way. I don't see idling clients as a big problem, when we crunch throguh 3k requests / hour at the same time, and when incomingin higher priority requests are still immediately processed.