Greeting everyone, I had an idea and wanted to see i it was good or not.
I have been thinking about ways to improve our joining algs. This proposal mostly apply to the attribute table join. I want to improve the spatial join too to reach speed similar to esri's but I'm not sure how they do it. I thought that we could possibly speed up and provide more flexibility by using hashes, this way we could also multi-attribute join ( as it was recently implemented for the table join). The idea would be to get the desired field (or fields) in the selected order. Make a QHash< QVarList, QFeatureIds>. This would require to go through both features once for mapping and another time for extraction/joining. We could also cache the full list of selected attributes instead of the featureids but this would take up more memory but prevent the extraction step. Is that a good idea or is it more wasteful/slow that the current implementation? Alex
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