[Community] Re: PrimaGIS 0.6-pre Performance

[Ludwig Max Brinckmann]

Back from holiday I had a little more time to investigate my performance
problem.
I have now traced this back to one of my default layers, which explains why
the performance problem was noticable with all types of datastores.

This default layer produces the blue stencil around Yunnan province in my
map and  is a simple polygon shapefile.
There are no rules defined for this layer (the polygon is simply blue) and
so I would not have thought that checking the box for python evaluation of
rules would make any difference: after all if there is nothing to evaluate
there should not be any noticable difference. Yet the difference in
rendering is an astonishing 17 seconds! Turning python evaluation off makes
rendering as fast as before. I have not spent any time looking further into
the reason for this, but it might be worthwhile investigating this
behaviour.

Just a few numbers (I just added some logging to PCL, sorry no line numbers
but Sean probably knows where this is):

First with python evaluation for rules (as said before no rules are present)
2006-07-29 01:03:52,244 INFO In PCL render
2006-07-29 01:03:52,275 INFO Rendering Layers
2006-07-29 01:03:52,278 INFO Rendering layer
<cartography.mapping.Layerinstance at 0xa9ad20c>
2006-07-29 01:03:52,396 INFO Rendering layer
<cartography.mapping.Layerinstance at 0xa9ad4cc>
2006-07-29 01:04:09,379 INFO Saving map
2006-07-29 01:04:11,154 INFO Saved map
2006-07-29 01:04:11,155 INFO About to return
2006-07-29 01:04:11,157 INFO Converting image
2006-07-29 01:04:11,345 INFO Converted image
Total time almost 20secs

This time without python eval:

2006-07-29 01:05:21,891 INFO In PCL render
2006-07-29 01:05:21,924 INFO Rendering Layers
2006-07-29 01:05:21,925 INFO Rendering layer
<cartography.mapping.Layerinstance at 0x458abf0c>
2006-07-29 01:05:22,050 INFO Rendering layer
<cartography.mapping.Layerinstance at 0xa762f6c>
2006-07-29 01:05:22,190 INFO Saving map
2006-07-29 01:05:22,194 INFO Saved map
2006-07-29 01:05:22,195 INFO About to return
2006-07-29 01:05:22,196 INFO Converting image
2006-07-29 01:05:22,446 INFO Converted image
Total time about 0.6 seconds.

HTH

Ludwig
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