Merge pull request #680 from ddanielvaz/master

Fix #7822. Export to Spatialite is really slow, compared to commandline ogr2ogr

Author: NathanW2

src/core/qgsvectorfilewriter.cpp

@@ -801,6 +801,16 @@ QgsVectorFileWriter::writeAsVectorFormat( QgsVectorLayer* layer,
 
   writer->startRender( layer );
 
+  // enabling transaction on databases that support it
+  bool transactionsEnabled = true;
+  OGRLayerH ogrCurrentLayer = writer->getLayer();
+
+  if ( OGRERR_NONE != OGR_L_StartTransaction(ogrCurrentLayer) )
+  {
+    QgsDebugMsg("Error when trying to enable transactions on OGRLayer.");
+    transactionsEnabled = false;
+  }
+
   // write all features
   while ( fit.nextFeature( fet ) )
   {
@@ -862,6 +872,14 @@ QgsVectorFileWriter::writeAsVectorFormat( QgsVectorLayer* layer,
     n++;
   }
 
+  if ( transactionsEnabled )
+  {
+    if ( OGRERR_NONE != OGR_L_CommitTransaction(ogrCurrentLayer) )
+    {
+      QgsDebugMsg("Error while commiting transaction on OGRLayer.");
+    }
+  }
+
   writer->stopRender( layer );
   delete writer;
 

src/core/qgsvectorfilewriter.h

@@ -154,6 +154,9 @@ class CORE_EXPORT QgsVectorFileWriter
 
     double symbologyScaleDenominator() const { return mSymbologyScaleDenominator; }
     void setSymbologyScaleDenominator( double d ) { mSymbologyScaleDenominator = d; }
+    
+    /**Returns OGRLayer used to begin and commit transactions on database*/
+    OGRLayerH getLayer() { return mLayer; }
 
   protected:
     //! @note not available in python bindings