diff --git a/chainerui/tasks/crawl_result.py b/chainerui/tasks/crawl_result.py
index a92b08f1..810972f0 100644
--- a/chainerui/tasks/crawl_result.py
+++ b/chainerui/tasks/crawl_result.py
@@ -65,7 +65,7 @@ def _check_log_updated(result):
     return False
 
 
-def crawl_result(result, force=False):
+def crawl_result(result, force=False, commit=True):
     """crawl_results."""
     now = datetime.datetime.now()
 
@@ -102,6 +102,7 @@ def crawl_result(result, force=False):
             )
 
     result.updated_at = datetime.datetime.now()
-    db.session.commit()
+    if commit:
+        db.session.commit()
 
     return result
diff --git a/chainerui/views/result.py b/chainerui/views/result.py
index e680814b..c5bdccb9 100644
--- a/chainerui/views/result.py
+++ b/chainerui/views/result.py
@@ -34,14 +34,16 @@ def get(self, id=None, project_id=None):
                 filter_by(is_unregistered=False).\
                 all()
 
+            # NOTE: To improve performance, aggregate commit phase. By set
+            # `commit=False`, implicit transaction is not closed, UPDATE query
+            # is not committed. Consequently a process of serializing does not
+            # have to call SELECT query again.
             for result in results:
-                result = crawl_result(result)
+                crawl_result(result, commit=False)
+            rs = [r.serialize_with_sampled_logs(logs_limit) for r in results]
+            db.session.commit()
 
-            return jsonify({
-                'results': [
-                    r.serialize_with_sampled_logs(logs_limit) for r in results
-                ]
-            })
+            return jsonify({'results': rs})
 
         else: