subtle postgis optimization re: bbox formation

[mapserver-bot]

Reporter: springmeyer
Date: 2011/09/15 - 23:34
In testing mapnik rendering against postgis I've played with using either BOX3D or GeomFromText to construct the geometry to use for bbox tests. I've noticed that using BOX3D is about 100 ms faster. Not sure if this is significant but just in case it might be faster I thought I would mention it (feel free to close). Mapnik code is here: http://trac.mapnik.org/browser/trunk/plugins/input/postgis/postgis_datasource.cpp#L360

And here was the simple benchmark (using the style from the foss4g2011 wms benchmark) in mapnik format:

mapnik-speed-check foss4g-2011/map.xml 3 -11486337,4785617.3,-11486283,4785655.2

# GeomFromText
min: 1299.6ms | avg: 1332.3ms | total: 3.9968s
min: 1296.9ms | avg: 1298.9ms | total: 3.8968s

# box3d
min: 1097.2ms | avg: 1098.9ms | total: 3.2968s
min: 1096.8ms | avg: 1098.9ms | total: 3.2968s

[mapserver-bot]

Author: pramsey
Date: 2011/09/16 - 17:11
100ms is a freaking eternity. I'll have to see if I can reproduce this. Thanks for the note.

[mapserver-bot]

Author: springmeyer
Date: 2011/09/16 - 21:31
k. if you have any trouble reproducing just ping here and I will look more into it on the mapnik side.