[Tile-serving] Improving Render Times

[Marcos Dione]

On Sun, Jun 16, 2019 at 04:37:31PM -0300, JunkMail wrote:
> Here are some benchmarks:
> 
> Total for all tiles rendered
> Meta tiles rendered: Rendered 349391 tiles in 420199.62 seconds (0.83
> tiles/s)
> Total tiles rendered: Rendered 22361024 tiles in 420199.62 seconds (53.22
> tiles/s)
> Total tiles handled: Rendered 349504 tiles in 420199.62 seconds (0.83
> tiles/s)
> *****************************************************
> Zoom 06: min:  0.3    avg: 47.4     max: 1932.3     over a total of  
> 2702.3s in 57 requests
> Zoom 07: min:  0.3    avg: 13.7     max: 1806.6     over a total of  
> 3373.8s in 247 requests
> Zoom 08: min:  0.4    avg:  4.2     max: 652.1     over a total of   4293.0s
> in 1010 requests
> Zoom 09: min:  0.4    avg:  1.7     max: 425.8     over a total of   6737.1s
> in 4079 requests
> Zoom 10: min:  0.4    avg:  4.2     max: 1353.2     over a total of 
> 69453.8s in 16368 requests
> Zoom 11: min:  0.4    avg:  1.5     max: 636.8     over a total of 100399.6s
> in 65506 requests
> Zoom 12: min:  0.4    avg:  0.9     max: 214.0     over a total of 233220.1s
> in 262124 requests
> *****************************************************
> 
> As you can see, it's quite slow at times. Even generating the cache took
> much longer than I would like.
> 
> Is there anything I can do to get some more speed out of it? It seems to be
> SSD bottlenecked, not CPU bottlenecked.

    Maybe it's related to these kind of patches:

https://github.com/gravitystorm/openstreetmap-carto/issues/3534

    To be honest, I have more or less the same problem, and I don't have
enough SQL benchmarking knowledge to follow all the comments in this and
other similar issues.

    Cheers,

	-- Marcos.

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