Fix #8434 (join by spatial location locks up QGIS)

wonder-sk · wonder-sk · commit c465c9f03d5e · 2014-02-10T14:47:51.000+07:00
By caching the features of the provider in the inner loop, there is
a considerable speedup (compared to doing millions of queries)
diff --git a/python/plugins/fTools/tools/doSpatialJoin.py b/python/plugins/fTools/tools/doSpatialJoin.py
@@ -168,6 +168,12 @@ def compute(self, inName, joinName, outName, summary, sumList, keep, progressBar
         add = 85.00 / provider1.featureCount()
 
         index = ftools_utils.createIndex(provider2)
+
+        # cache all features from provider2 to avoid huge number of feature requests in the inner loop
+        mapP2 = {}
+        for f in provider2.getFeatures():
+            mapP2[f.id()] = QgsFeature(f)
+
         fit1 = provider1.getFeatures()
         while fit1.nextFeature(inFeat):
             inGeom = inFeat.geometry()
@@ -192,8 +198,7 @@ def compute(self, inName, joinName, outName, summary, sumList, keep, progressBar
             if check == 0:
                 count = 0
                 for i in joinList:
-                    #tempGeom = i.geometry()
-                    provider2.getFeatures( QgsFeatureRequest().setFilterFid( int(i) ) ).nextFeature( inFeatB )
+                    inFeatB = mapP2[i]  # cached feature from provider2
                     if inGeom.intersects(inFeatB.geometry()):
                         count = count + 1
                         none = False
