Optimize to avoid 502 errors caused by multiple queries

app/views/admin/seminars/export.xlsx.axlsx

@@ -52,6 +52,15 @@ wb.add_worksheet(name: sheet_name) do |sheet|
   wrap_text_style = wb.styles.add_style({:alignment => {:horizontal => :center, :vertical => :center, :wrap_text => true}})
   types = [:time]
   styles = [date_time_style]
+  
+  # 優化：一次性載入所有資料，避免 N+1 查詢
+  signup_ids = @seminar_signups.map(&:id)
+  signup_values_index = {}
+  SeminarSignupValue.where(:seminar_signup_id.in => signup_ids).each do |sv|
+    key = "#{sv.seminar_signup_id}_#{sv.seminar_signup_field_id}"
+    signup_values_index[key] = sv
+  end
+  
   @seminar_signups.each_with_index do |signup, i|
     row2 = []
     row2 << signup.created_at
@@ -65,12 +74,14 @@ wb.add_worksheet(name: sheet_name) do |sheet|
     row2 << "#{signup[:email]} "
     row2 << "#{signup.note} "
     seminar_signup_fields.each do |rf|
+      key = "#{signup.id}_#{rf.id}"
+      signup_value = signup_values_index[key]
       if rf.can_muti_lang_input?
         @site_in_use_locales.each do |l|
-          row2 << (@seminar.get_attribute_value(rf,signup.id).get_value_by_locale(l) rescue '')
+          row2 << (signup_value&.get_value_by_locale(l) rescue '')
         end
       else
-        row2 << (@seminar.get_attribute_value(rf,signup.id).get_value_by_locale(I18n.locale) rescue '')
+        row2 << (signup_value&.get_value_by_locale(I18n.locale) rescue '')
       end
     end
     if i == 0
@@ -82,4 +93,4 @@ wb.add_worksheet(name: sheet_name) do |sheet|
     sheet.add_row row2 , :types => types, :style => styles
   end
 
-end
+end