diff --git a/src/providers/postgres/qgspostgresfeatureiterator.cpp b/src/providers/postgres/qgspostgresfeatureiterator.cpp
index 162390f7002c..6d05950484c7 100644
--- a/src/providers/postgres/qgspostgresfeatureiterator.cpp
+++ b/src/providers/postgres/qgspostgresfeatureiterator.cpp
@@ -293,7 +293,6 @@ QString QgsPostgresFeatureIterator::whereClauseRect()
 bool QgsPostgresFeatureIterator::declareCursor( const QString& whereClause )
 {
   mFetchGeometry = !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) && !P->mGeometryColumn.isNull();
-  bool simplifyGeometry = false;
 
   try
   {
@@ -304,11 +303,10 @@ bool QgsPostgresFeatureIterator::declareCursor( const QString& whereClause )
     if ( mFetchGeometry && !simplifyMethod.forceLocalOptimization() && simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification && QGis::flatType( QGis::singleType( P->geometryType() ) ) != QGis::WKBPoint )
     {
       QString simplifyFunctionName = simplifyMethod.methodType() == QgsSimplifyMethod::OptimizeForRendering
-                                     ? ( P->mConnectionRO->majorVersion() < 2 ? "simplify" : "st_simplify" )
+                                     ? ( P->mConnectionRO->majorVersion() < 2 ? "snaptogrid" : "st_snaptogrid" )
                                          : ( P->mConnectionRO->majorVersion() < 2 ? "simplifypreservetopology" : "st_simplifypreservetopology" );
 
       double tolerance = simplifyMethod.tolerance() * 0.8; //-> Default factor for the maximum displacement distance for simplification, similar as GeoServer does
-      simplifyGeometry = simplifyMethod.methodType() == QgsSimplifyMethod::OptimizeForRendering;
 
       query += QString( "%1(%5(%2%3,%6),'%4')" )
                .arg( P->mConnectionRO->majorVersion() < 2 ? "asbinary" : "st_asbinary" )
@@ -369,17 +367,6 @@ bool QgsPostgresFeatureIterator::declareCursor( const QString& whereClause )
       query += delim + P->mConnectionRO->fieldExpression( P->field( idx ) );
     }
 
-    // query BBOX of geometries to redefine the geometries collapsed by ST_Simplify()
-    if ( simplifyGeometry && !( P->mConnectionRO->majorVersion() >= 2 && P->mConnectionRO->minorVersion() >= 1 ) )
-    {
-      query += QString( ",%1(%5(%2)%3,'%4')" )
-               .arg( P->mConnectionRO->majorVersion() < 2 ? "asbinary" : "st_asbinary" )
-               .arg( P->quotedIdentifier( P->mGeometryColumn ) )
-               .arg( P->mSpatialColType == sctGeography ? "::geometry" : "" )
-               .arg( P->endianString() )
-               .arg( P->mConnectionRO->majorVersion() < 2 ? "envelope" : "st_envelope" );
-    }
-
     query += " FROM " + P->mQuery;
 
     if ( !whereClause.isEmpty() )
@@ -603,43 +590,6 @@ bool QgsPostgresFeatureIterator::getFeature( QgsPostgresResult &queryResult, int
         getFeatureAttribute( idx, queryResult, row, col, feature );
     }
 
-    // fix collapsed geometries by ST_Simplify() using the BBOX fetched from the current query
-    const QgsSimplifyMethod& simplifyMethod = mRequest.simplifyMethod();
-    if ( mFetchGeometry && !simplifyMethod.forceLocalOptimization() && simplifyMethod.methodType() == QgsSimplifyMethod::OptimizeForRendering && QGis::flatType( QGis::singleType( P->geometryType() ) ) != QGis::WKBPoint )
-    {
-      QgsGeometry* geometry = feature.geometry();
-
-      if ( !( P->mConnectionRO->majorVersion() >= 2 && P->mConnectionRO->minorVersion() >= 1 ) && ( !geometry || geometry->length() == 0 ) )
-      {
-        int returnedLength = ::PQgetlength( queryResult.result(), row, col );
-
-        if ( returnedLength > 0 )
-        {
-          unsigned char *featureGeom = new unsigned char[returnedLength + 1];
-          memcpy( featureGeom, PQgetvalue( queryResult.result(), row, col ), returnedLength );
-          memset( featureGeom + returnedLength, 0, 1 );
-
-          QgsGeometry *envelope = new QgsGeometry();
-          envelope->fromWkb( featureGeom, returnedLength + 1 );
-
-          if ( QGis::flatType( QGis::singleType( P->geometryType() ) ) == QGis::WKBPolygon )
-          {
-            feature.setGeometry( envelope );
-          }
-          else
-          {
-            QgsPolyline polyline;
-            polyline.append( envelope->vertexAt( 0 ) );
-            polyline.append( envelope->vertexAt( 2 ) );
-            delete envelope;
-
-            geometry = QgsGeometry::fromPolyline( polyline );
-            feature.setGeometry( geometry );
-          }
-        }
-      }
-    }
-
     return true;
   }
   catch ( QgsPostgresProvider::PGFieldNotFound )