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Updated Postgis async (markdown)

Bonnasseau 2013-09-24 10:05:55 -07:00
parent 4e5e07d560
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Postgis-async.md

@ -99,9 +99,10 @@ Let's consider the number of geographical features for 7 layers :
For the example, we will assume database query time and drawing time are equal and proportional to the number of features in the layer (1).
The largest layer is *roads* ; it is 4 time larger thant the others. Hence we should launch the query to get the features for roads before the drawing of layer *urban areas*, so that the query is finished when the drawing of roads is about to start.
The largest layer is *roads* ; it is 4 time larger thant the others. Hence we should launch the query to get the features for roads before the drawing of layer *urban areas*, so that the query is finished when the drawing of roads is about to start. So `max_async_connection` can be set to 4.
If you have no idea at all, **4** is a good start.
Anyway, if you have no idea at all, **4** is a good start.
(1) If you use two identical servers, and you have optimized layers according to [rendering optimizations with PoistGIS](OptimizeRenderingWithPostGIS), you can assume queries and drawing are about the same time, except for drawing labels that are slower than queries.