diff --git a/frontend/src/frameworks/components/charts/EChartsBase.tsx b/frontend/src/frameworks/components/charts/EChartsBase.tsx
index 665cf84..c4629e9 100644
--- a/frontend/src/frameworks/components/charts/EChartsBase.tsx
+++ b/frontend/src/frameworks/components/charts/EChartsBase.tsx
@@ -53,8 +53,12 @@ export const EChartsBase: React.FC<EChartsBaseProps> = ({
 
   // Update option
   useEffect(() => {
-    if (!chartRef.current) return;
-    chartRef.current.setOption(option, { notMerge: true });
+    if (!chartRef.current || !option) return;
+    try {
+      chartRef.current.setOption(option, { notMerge: true });
+    } catch (e) {
+      console.warn('ECharts setOption error:', e);
+    }
   }, [option]);
 
   // Handle loading state
diff --git a/frontend/src/frameworks/hooks/useImportData.ts b/frontend/src/frameworks/hooks/useImportData.ts
index d3a4cb8..07fa96f 100644
--- a/frontend/src/frameworks/hooks/useImportData.ts
+++ b/frontend/src/frameworks/hooks/useImportData.ts
@@ -60,8 +60,9 @@ export function useImportData() {
         try {
           const rowsResp = await dataServiceClient.getRows(dataSetId, 10000);
           rows = rowsResp.rows ?? rowsResp ?? [];
-        } catch {
-          // rows fetch failed, continue without
+          console.log(`[DataViz] Fetched ${rows.length} rows for dataset ${dataSetId}`);
+        } catch (e) {
+          console.error('[DataViz] Failed to fetch rows:', e);
         }
 
         const dataSet = mapBackendDataSet(rawDataSet, rows);