diff --git a/client/jsFiles/SEAWebClientGraphics.js b/client/jsFiles/SEAWebClientGraphics.js
index 5531a6a..12e9431 100644
--- a/client/jsFiles/SEAWebClientGraphics.js
+++ b/client/jsFiles/SEAWebClientGraphics.js
@@ -292,6 +292,7 @@ let graphs = (function (){
 
     let created = false;
     let activateUpdateTimeout = undefined;
+    let updateAutoTimeout = undefined;
 
     let container = document.createElement('div');
     container.classList.add("graphs-container");
@@ -1258,6 +1259,19 @@ let graphs = (function (){
         }
     }
 
+    function onZoomCompleteCallback(){
+        if (updateAutoTimeout === undefined){
+            updateAutoTimeout = setTimeout(function() {
+            updateAuto();
+            updateAutoTimeout = undefined;
+            }, 100);
+        }
+        else{
+            clearTimeout(updateAutoTimeout);
+            updateAutoTimeout = undefined;
+        }
+    }
+
     return {
         addDataset: addDataset,
         //toggleAxesType: toggleAxesType,
@@ -1291,6 +1305,7 @@ let graphs = (function (){
         shiftNewer: shiftNewer,
         jumpToDate: jumpToDate,
         initGraphs: initGraphs,
+        onZoomCompleteCallback:onZoomCompleteCallback,
     }
 })();
 
@@ -1431,7 +1446,7 @@ function Graph(gindex, container, x_label, y_label, tag, scaleType = "linear"){
                 sensitivity: 1,
                 onZoom: function({chart}) { graphs.zoomCallback(chart.graph);},
                 //onZoomComplete: function({chart}){graphs.checkReload(chart.graph);redraw()},
-                onZoomComplete: function({chart}){graphs.updateAuto();},
+                onZoomComplete: function({chart}){graphs.onZoomCompleteCallback()},
             }
         }
     });
diff --git a/influxdb.py b/influxdb.py
index f24ee09..433ece0 100644
--- a/influxdb.py
+++ b/influxdb.py
@@ -121,6 +121,7 @@ class InfluxDataGetter:
                 variable_name_for_query = variable_name_for_query[:-len(".target")]
                 is_target = True
             start_time = int(lastvalues[variable_name_for_query][0]) if variable_name_for_query in lastvalues.keys() else None
+            start_time = start_time if start_time != None and start_time <= end_time else None # to prevent self.lastvalues being changed by w_graph between entrance of graphpoll and poll_last_values
             points = self._get_last_values(variable_name_for_query, is_target,start_time, end_time)
             if len(points) > 0 :
                 res[variable] = points