Merge pull request rails#41256 from eileencodes/revert-qc-changes

Revert qc changes

Author: eileencodes

activerecord/lib/active_record/query_cache.rb

@@ -26,26 +26,30 @@ def uncached(&block)
     end
 
     def self.run
+      pools = []
+
       if ActiveRecord::Base.legacy_connection_handling
-        ActiveRecord::Base.connection_handlers.each_value do |handler|
-          handler.connection_pool_list.each(&:enable_query_cache!)
+        ActiveRecord::Base.connection_handlers.each do |key, handler|
+          pools.concat(handler.connection_pool_list.reject { |p| p.query_cache_enabled }.each { |p| p.enable_query_cache! })
         end
       else
-        ActiveRecord::Base.connection_handler.all_connection_pools.each(&:enable_query_cache!)
+        pools.concat(ActiveRecord::Base.connection_handler.all_connection_pools.reject { |p| p.query_cache_enabled }.each { |p| p.enable_query_cache! })
       end
+
+      pools
     end
 
-    def self.complete(_)
+    def self.complete(pools)
+      pools.each { |pool| pool.disable_query_cache! }
+
       if ActiveRecord::Base.legacy_connection_handling
-        ActiveRecord::Base.connection_handlers.each_value do |handler|
+        ActiveRecord::Base.connection_handlers.each do |_, handler|
           handler.connection_pool_list.each do |pool|
-            pool.disable_query_cache!
             pool.release_connection if pool.active_connection? && !pool.connection.transaction_open?
           end
         end
       else
         ActiveRecord::Base.connection_handler.all_connection_pools.each do |pool|
-          pool.disable_query_cache!
           pool.release_connection if pool.active_connection? && !pool.connection.transaction_open?
         end
       end