#434

backend/app/services/counts_population.rb

@@ -41,8 +41,7 @@ class CountsPopulation
     raise ArgumentError
   end
 
-  def latest_sql(row = 'v', cutoff = nil)
-    cutoff ||= history ? at : timestamp(params['at']) || at
+  def latest_at_sql(row, cutoff)
     keys = definition.keys.map { "newer.#{ _1 } = #{ row }.#{ _1 }" }.join(' AND ')
     bound = definition.model.connection.quote(cutoff)
     <<~SQL.squish
@@ -52,6 +51,14 @@ class CountsPopulation
     SQL
   end
 
+  def current_latest_sql(row = 'v')
+    keys = definition.keys.map { "newer.#{ _1 } = #{ row }.#{ _1 }" }.join(' AND ')
+    <<~SQL.squish
+      NOT EXISTS (SELECT 1 FROM #{ definition.table } newer
+        WHERE #{ keys } AND newer.version_no > #{ row }.version_no)
+    SQL
+  end
+
   def changed_sql(key)
     column = definition.column(key)
     "(previous.id IS NOT NULL AND NOT (v.#{ column } <=> previous.#{ column }))"
@@ -125,7 +132,7 @@ class CountsPopulation
       raise ArgumentError if point > at
 
       @scope = @scope.where("v.#{ definition.time_column } <= ?", point)
-          .where(Arel.sql(latest_sql('v', point))).where.not('v.event_type' => 'discard')
+          .where(Arel.sql(latest_at_sql('v', point))).where.not('v.event_type' => 'discard')
       return
     end
     first = timestamp(params['from'])