diff --git a/.gitignore b/.gitignore
index ba60fe2269a..e84b6ecec45 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *.*~
+*.autosave
 *.aux
 *.diff
 *.log*
diff --git a/python/core/symbology-ng/qgscategorizedsymbolrendererv2.sip b/python/core/symbology-ng/qgscategorizedsymbolrendererv2.sip
index beafd1af747..566b778d33c 100644
--- a/python/core/symbology-ng/qgscategorizedsymbolrendererv2.sip
+++ b/python/core/symbology-ng/qgscategorizedsymbolrendererv2.sip
@@ -49,7 +49,7 @@ class QgsCategorizedSymbolRendererV2 : QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 
diff --git a/python/core/symbology-ng/qgsgraduatedsymbolrendererv2.sip b/python/core/symbology-ng/qgsgraduatedsymbolrendererv2.sip
index 2f8ed306b06..3c79444c304 100644
--- a/python/core/symbology-ng/qgsgraduatedsymbolrendererv2.sip
+++ b/python/core/symbology-ng/qgsgraduatedsymbolrendererv2.sip
@@ -91,7 +91,7 @@ class QgsGraduatedSymbolRendererV2 : QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 
diff --git a/python/core/symbology-ng/qgsheatmaprenderer.sip b/python/core/symbology-ng/qgsheatmaprenderer.sip
index 0f2aaf1de0d..fca3100a5cd 100644
--- a/python/core/symbology-ng/qgsheatmaprenderer.sip
+++ b/python/core/symbology-ng/qgsheatmaprenderer.sip
@@ -10,7 +10,7 @@ class QgsHeatmapRenderer : QgsFeatureRendererV2
 
     //reimplemented methods
     virtual QgsFeatureRendererV2* clone() const /Factory/;
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false );
     virtual void stopRender( QgsRenderContext& context );
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature );
diff --git a/python/core/symbology-ng/qgsinvertedpolygonrenderer.sip b/python/core/symbology-ng/qgsinvertedpolygonrenderer.sip
index 0361f0f7df2..273da0959cf 100644
--- a/python/core/symbology-ng/qgsinvertedpolygonrenderer.sip
+++ b/python/core/symbology-ng/qgsinvertedpolygonrenderer.sip
@@ -14,7 +14,7 @@ class QgsInvertedPolygonRenderer : QgsFeatureRendererV2
     /** Used to clone this feature renderer.*/
     virtual QgsFeatureRendererV2* clone() const /Factory/;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     /** Renders a given feature.
      * This will here collect features. The actual rendering will be postponed to stopRender()
diff --git a/python/core/symbology-ng/qgspointdisplacementrenderer.sip b/python/core/symbology-ng/qgspointdisplacementrenderer.sip
index d44871732ab..55163e022d6 100644
--- a/python/core/symbology-ng/qgspointdisplacementrenderer.sip
+++ b/python/core/symbology-ng/qgspointdisplacementrenderer.sip
@@ -16,7 +16,7 @@ class QgsPointDisplacementRenderer : QgsFeatureRendererV2
 
     QgsSymbolV2* symbolForFeature( QgsFeature& feature );
 
-    void startRender( QgsRenderContext& context, const QgsFields& fields );
+    QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     void stopRender( QgsRenderContext& context );
 
diff --git a/python/core/symbology-ng/qgsrendererv2.sip b/python/core/symbology-ng/qgsrendererv2.sip
index ff6ea841895..6b137ef4fdb 100644
--- a/python/core/symbology-ng/qgsrendererv2.sip
+++ b/python/core/symbology-ng/qgsrendererv2.sip
@@ -17,6 +17,16 @@ class QgsSymbolV2LevelItem
     int layer();
 };
 
+class QgsRenderOptions
+{
+%TypeHeaderCode
+#include <qgsrendererv2.h>
+%End
+  public:
+    void setWhereClause( const QString& whereClause );
+    QString whereClause();
+};
+
 // every level has list of items: symbol + symbol layer num
 // typedef QList< QgsSymbolV2LevelItem > QgsSymbolV2Level;
 
@@ -74,7 +84,7 @@ class QgsFeatureRendererV2
      */
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
 
     //! @deprecated since 2.4 - not using QgsVectorLayer directly anymore
     virtual void startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer ) /Deprecated/;
diff --git a/python/core/symbology-ng/qgsrulebasedrendererv2.sip b/python/core/symbology-ng/qgsrulebasedrendererv2.sip
index b7df2d32fef..cdc5f6c02ff 100644
--- a/python/core/symbology-ng/qgsrulebasedrendererv2.sip
+++ b/python/core/symbology-ng/qgsrulebasedrendererv2.sip
@@ -173,7 +173,7 @@ class QgsRuleBasedRendererV2 : QgsFeatureRendererV2
 
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 
diff --git a/python/core/symbology-ng/qgssinglesymbolrendererv2.sip b/python/core/symbology-ng/qgssinglesymbolrendererv2.sip
index bf9e39d5748..eb734770a3a 100644
--- a/python/core/symbology-ng/qgssinglesymbolrendererv2.sip
+++ b/python/core/symbology-ng/qgssinglesymbolrendererv2.sip
@@ -13,7 +13,7 @@ class QgsSingleSymbolRendererV2 : QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature );
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields );
 
     virtual void stopRender( QgsRenderContext& context );
 
diff --git a/src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp b/src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp
index a85d49a82e7..f8d4c618e2d 100644
--- a/src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp
+++ b/src/core/symbology-ng/qgscategorizedsymbolrendererv2.cpp
@@ -396,7 +396,7 @@ void QgsCategorizedSymbolRendererV2::sortByLabel( Qt::SortOrder order )
   }
 }
 
-void QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   mCounting = context.rendererScale() == 0.0;
 
@@ -425,6 +425,7 @@ void QgsCategorizedSymbolRendererV2::startRender( QgsRenderContext& context, con
       mTempSymbols[ it->symbol()] = tempSymbol;
     }
   }
+  return QgsRenderOptions();
 }
 
 void QgsCategorizedSymbolRendererV2::stopRender( QgsRenderContext& context )
diff --git a/src/core/symbology-ng/qgscategorizedsymbolrendererv2.h b/src/core/symbology-ng/qgscategorizedsymbolrendererv2.h
index bd111c83848..c2b78369990 100644
--- a/src/core/symbology-ng/qgscategorizedsymbolrendererv2.h
+++ b/src/core/symbology-ng/qgscategorizedsymbolrendererv2.h
@@ -79,7 +79,7 @@ class CORE_EXPORT QgsCategorizedSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;
 
diff --git a/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp b/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp
index 8318f476e59..e86b3946a3f 100644
--- a/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp
+++ b/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.cpp
@@ -369,7 +369,7 @@ QgsSymbolV2* QgsGraduatedSymbolRendererV2::originalSymbolForFeature( QgsFeature&
   return symbolForValue( value.toDouble() );
 }
 
-void QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   mCounting = context.rendererScale() == 0.0;
 
@@ -399,6 +399,7 @@ void QgsGraduatedSymbolRendererV2::startRender( QgsRenderContext& context, const
       mTempSymbols[ it->symbol()] = tempSymbol;
     }
   }
+  return QgsRenderOptions();
 }
 
 void QgsGraduatedSymbolRendererV2::stopRender( QgsRenderContext& context )
diff --git a/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.h b/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.h
index 068a2ec7d54..8086176761f 100644
--- a/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.h
+++ b/src/core/symbology-ng/qgsgraduatedsymbolrendererv2.h
@@ -123,7 +123,7 @@ class CORE_EXPORT QgsGraduatedSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;
 
diff --git a/src/core/symbology-ng/qgsheatmaprenderer.cpp b/src/core/symbology-ng/qgsheatmaprenderer.cpp
index 65c46b0d6ac..307ab86855d 100644
--- a/src/core/symbology-ng/qgsheatmaprenderer.cpp
+++ b/src/core/symbology-ng/qgsheatmaprenderer.cpp
@@ -63,12 +63,12 @@ void QgsHeatmapRenderer::initializeValues( QgsRenderContext& context )
   mRadiusSquared = mRadiusPixels * mRadiusPixels;
 }
 
-void QgsHeatmapRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsHeatmapRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   Q_UNUSED( fields );
   if ( !context.painter() )
   {
-    return;
+    return QgsRenderOptions();
   }
 
   // find out classification attribute index from name
@@ -80,6 +80,7 @@ void QgsHeatmapRenderer::startRender( QgsRenderContext& context, const QgsFields
   }
 
   initializeValues( context );
+  return QgsRenderOptions();
 }
 
 QgsMultiPoint QgsHeatmapRenderer::convertToMultipoint( const QgsGeometry* geom )
diff --git a/src/core/symbology-ng/qgsheatmaprenderer.h b/src/core/symbology-ng/qgsheatmaprenderer.h
index 0e57ac16fb4..158255b1ab5 100644
--- a/src/core/symbology-ng/qgsheatmaprenderer.h
+++ b/src/core/symbology-ng/qgsheatmaprenderer.h
@@ -39,7 +39,7 @@ class CORE_EXPORT QgsHeatmapRenderer : public QgsFeatureRendererV2
 
     //reimplemented methods
     virtual QgsFeatureRendererV2* clone() const override;
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false ) override;
     virtual void stopRender( QgsRenderContext& context ) override;
     virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature ) override;
diff --git a/src/core/symbology-ng/qgsinvertedpolygonrenderer.cpp b/src/core/symbology-ng/qgsinvertedpolygonrenderer.cpp
index 816b81e7a7d..96944205859 100644
--- a/src/core/symbology-ng/qgsinvertedpolygonrenderer.cpp
+++ b/src/core/symbology-ng/qgsinvertedpolygonrenderer.cpp
@@ -63,11 +63,11 @@ const QgsFeatureRendererV2* QgsInvertedPolygonRenderer::embeddedRenderer() const
   return mSubRenderer.data();
 }
 
-void QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   if ( !mSubRenderer )
   {
-    return;
+    return QgsRenderOptions();
   }
 
   // first call start render on the sub renderer
@@ -85,7 +85,7 @@ void QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const Q
 
   if ( !context.painter() )
   {
-    return;
+    return QgsRenderOptions();
   }
 
   // convert viewport to dest CRS
@@ -119,6 +119,8 @@ void QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const Q
 
   mExtentPolygon.clear();
   mExtentPolygon.append( exteriorRing );
+
+  return QgsRenderOptions();
 }
 
 bool QgsInvertedPolygonRenderer::renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer, bool selected, bool drawVertexMarker )
diff --git a/src/core/symbology-ng/qgsinvertedpolygonrenderer.h b/src/core/symbology-ng/qgsinvertedpolygonrenderer.h
index 1e8ad605f65..13c14304100 100644
--- a/src/core/symbology-ng/qgsinvertedpolygonrenderer.h
+++ b/src/core/symbology-ng/qgsinvertedpolygonrenderer.h
@@ -50,7 +50,7 @@ class CORE_EXPORT QgsInvertedPolygonRenderer : public QgsFeatureRendererV2
     /** Used to clone this feature renderer.*/
     virtual QgsFeatureRendererV2* clone() const override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     /** Renders a given feature.
      * This will here collect features. The actual rendering will be postponed to stopRender()
diff --git a/src/core/symbology-ng/qgspointdisplacementrenderer.cpp b/src/core/symbology-ng/qgspointdisplacementrenderer.cpp
index 046d92dff38..a755983062b 100644
--- a/src/core/symbology-ng/qgspointdisplacementrenderer.cpp
+++ b/src/core/symbology-ng/qgspointdisplacementrenderer.cpp
@@ -279,7 +279,7 @@ bool QgsPointDisplacementRenderer::willRenderFeature( QgsFeature& feat )
 }
 
 
-void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   mRenderer->startRender( context, fields );
 
@@ -310,6 +310,7 @@ void QgsPointDisplacementRenderer::startRender( QgsRenderContext& context, const
   {
     mCenterSymbol->startRender( context, &fields );
   }
+  return QgsRenderOptions();
 }
 
 void QgsPointDisplacementRenderer::stopRender( QgsRenderContext& context )
diff --git a/src/core/symbology-ng/qgspointdisplacementrenderer.h b/src/core/symbology-ng/qgspointdisplacementrenderer.h
index a908958ee22..5d5f286132e 100644
--- a/src/core/symbology-ng/qgspointdisplacementrenderer.h
+++ b/src/core/symbology-ng/qgspointdisplacementrenderer.h
@@ -58,7 +58,7 @@ class CORE_EXPORT QgsPointDisplacementRenderer: public QgsFeatureRendererV2
     /** Proxy that will call this method on the embedded renderer. */
     virtual bool willRenderFeature( QgsFeature& feat ) override;
 
-    void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     void stopRender( QgsRenderContext& context ) override;
 
diff --git a/src/core/symbology-ng/qgsrendererv2.h b/src/core/symbology-ng/qgsrendererv2.h
index f9dffcb5cbf..2fad4e5f291 100644
--- a/src/core/symbology-ng/qgsrendererv2.h
+++ b/src/core/symbology-ng/qgsrendererv2.h
@@ -61,6 +61,15 @@ class CORE_EXPORT QgsSymbolV2LevelItem
     int mLayer;
 };
 
+class CORE_EXPORT QgsRenderOptions
+{
+  public:
+    void setWhereClause( const QString& whereClause ) { mWhereClause = whereClause; }
+    QString whereClause() { return mWhereClause; }
+  private:
+    QString mWhereClause;
+};
+
 // every level has list of items: symbol + symbol layer num
 typedef QList< QgsSymbolV2LevelItem > QgsSymbolV2Level;
 
@@ -95,7 +104,14 @@ class CORE_EXPORT QgsFeatureRendererV2
      */
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) { return symbolForFeature( feature ); }
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
+    /**
+     * Needs to be called when a new render cycle is started
+     *
+     * @param context  Additional information passed to the renderer about the job which will be rendered
+     * @param fields   The fields available for rendering
+     * @return         Information passed back from the renderer that can e.g. be used to reduce the amount of requested features
+     */
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) = 0;
 
     //! @deprecated since 2.4 - not using QgsVectorLayer directly anymore
     Q_DECL_DEPRECATED virtual void startRender( QgsRenderContext& context, const QgsVectorLayer* vlayer );
diff --git a/src/core/symbology-ng/qgsrulebasedrendererv2.cpp b/src/core/symbology-ng/qgsrulebasedrendererv2.cpp
index 0dc9ef62120..f29a4077b2b 100644
--- a/src/core/symbology-ng/qgsrulebasedrendererv2.cpp
+++ b/src/core/symbology-ng/qgsrulebasedrendererv2.cpp
@@ -779,7 +779,7 @@ bool QgsRuleBasedRendererV2::renderFeature( QgsFeature& feature,
 }
 
 
-void QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
   // prepare active children
   mRootRule->startRender( context, fields );
@@ -800,6 +800,7 @@ void QgsRuleBasedRendererV2::startRender( QgsRenderContext& context, const QgsFi
   }
 
   mRootRule->setNormZLevels( zLevelsToNormLevels );
+  return QgsRenderOptions();
 }
 
 void QgsRuleBasedRendererV2::stopRender( QgsRenderContext& context )
diff --git a/src/core/symbology-ng/qgsrulebasedrendererv2.h b/src/core/symbology-ng/qgsrulebasedrendererv2.h
index 39a7edb857d..19f0f5b04a2 100644
--- a/src/core/symbology-ng/qgsrulebasedrendererv2.h
+++ b/src/core/symbology-ng/qgsrulebasedrendererv2.h
@@ -220,7 +220,7 @@ class CORE_EXPORT QgsRuleBasedRendererV2 : public QgsFeatureRendererV2
 
     virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;
 
diff --git a/src/core/symbology-ng/qgssinglesymbolrendererv2.cpp b/src/core/symbology-ng/qgssinglesymbolrendererv2.cpp
index 67abc1fd6cf..0d14ed720ef 100644
--- a/src/core/symbology-ng/qgssinglesymbolrendererv2.cpp
+++ b/src/core/symbology-ng/qgssinglesymbolrendererv2.cpp
@@ -79,9 +79,10 @@ QgsSymbolV2* QgsSingleSymbolRendererV2::originalSymbolForFeature( QgsFeature& fe
   return mSymbol.data();
 }
 
-void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
+QgsRenderOptions QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const QgsFields& fields )
 {
-  if ( !mSymbol.data() ) return;
+  if ( !mSymbol.data() )
+    return QgsRenderOptions();
 
   mSymbol->startRender( context, &fields );
 
@@ -112,6 +113,8 @@ void QgsSingleSymbolRendererV2::startRender( QgsRenderContext& context, const Qg
       mOrigSize = 0;
     }
   }
+
+  return QgsRenderOptions();
 }
 
 void QgsSingleSymbolRendererV2::stopRender( QgsRenderContext& context )
diff --git a/src/core/symbology-ng/qgssinglesymbolrendererv2.h b/src/core/symbology-ng/qgssinglesymbolrendererv2.h
index 1a58fb005cb..ffce5053c18 100644
--- a/src/core/symbology-ng/qgssinglesymbolrendererv2.h
+++ b/src/core/symbology-ng/qgssinglesymbolrendererv2.h
@@ -33,7 +33,7 @@ class CORE_EXPORT QgsSingleSymbolRendererV2 : public QgsFeatureRendererV2
 
     virtual QgsSymbolV2* originalSymbolForFeature( QgsFeature& feature ) override;
 
-    virtual void startRender( QgsRenderContext& context, const QgsFields& fields ) override;
+    virtual QgsRenderOptions startRender( QgsRenderContext& context, const QgsFields& fields ) override;
 
     virtual void stopRender( QgsRenderContext& context ) override;