#4104 added checks (as cannot easily reproduce)

app/models/carto/visualization.rb

@@ -43,6 +43,10 @@ class Carto::Visualization < ActiveRecord::Base
 
   belongs_to :map
 
+  def ==(other_visualization)
+    self.id == other_visualization.id
+  end
+
   def size
     # Only canonical visualizations (Datasets) have a related table and then count against disk quota,
     # but we want to not break and even allow ordering by size multiple types

app/queries/carto/offdatabase_query_adapter.rb

@@ -55,6 +55,8 @@ module Carto
         all = all.sort { |x, y|
           x_attribute = is_array ? x.send(attribute).count : x.send(attribute)
           y_attribute = is_array ? y.send(attribute).count : y.send(attribute)
+          x_attribute = 0 if x_attribute.nil?
+          y_attribute = 0 if y_attribute.nil?
           asc_or_desc == :asc ? x_attribute <=> y_attribute : y_attribute <=> x_attribute
         }
       }