more perf

initialrenderer/renderer.go

@@ -21,6 +21,7 @@ func Render(tr *tilerenderer.TileRenderer,
     start := time.Now()
     complete_count := 512*512
     current_count := 0
+    perf_count := 0
 
     jobs := make(chan coords.TileCoords, 100)
 
@@ -37,6 +38,7 @@ func Render(tr *tilerenderer.TileRenderer,
     			tc := coords.NewTileCoords(x,y,10,layer.Id)
           jobs <- tc
           current_count++
+          perf_count++
 
           if time.Now().Sub(start).Seconds() > 2 {
             start = time.Now()
@@ -47,8 +49,10 @@ func Render(tr *tilerenderer.TileRenderer,
               "y": y,
               "progress%": progress,
               "layer": layer.Name,
+              "perf": perf_count,
             }
 
+            perf_count = 0
             logrus.WithFields(fields).Info("Initial render progress")
           }
     		}

tilerenderer/renderer.go

@@ -196,6 +196,13 @@ func (tr *TileRenderer) RenderImage(tc coords.TileCoords) (*image.NRGBA, error)
 		png.Encode(buf, img)
 	}
 
+	isEmpty := upperLeft == nil && upperRight == nil && lowerLeft == nil && lowerRight == nil
+
+	if isEmpty && (tc.Zoom == 12 || tc.Zoom == 11 || tc.Zoom == 10) {
+		//don't cache empty zoomed tiles
+		return nil, nil
+	}
+
 	tile := tiledb.Tile{Pos: tc, Data: buf.Bytes(), Mtime: time.Now().Unix()}
 	tr.tdb.SetTile(&tile)