diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 4e36fc176dc23bfb19961d1ac0230bcb4b86e2dc..70e48de9400076f327d248e1b0ecdf7d1dc0fed6 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -1027,7 +1027,7 @@ def connection_pool_names # :nodoc:
       end
 
       def connection_pool_list
-        owner_to_pool_manager.values.compact.flat_map { |m| m.pool_configs.map(&:pool) }
+        owner_to_pool_manager.values.flat_map { |m| m.pool_configs.map(&:pool) }
       end
       alias :connection_pools :connection_pool_list