Merge pull request rails#46661 from Shopify/clear-query-cache-deadlock

Use a single lock for all connections

Author: byroot

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -172,13 +172,19 @@ def initialize(config_or_deprecated_connection, deprecated_logger = nil, depreca
         @verified = false
       end
 
+      THREAD_LOCK = ActiveSupport::Concurrency::ThreadLoadInterlockAwareMonitor.new
+      private_constant :THREAD_LOCK
+
+      FIBER_LOCK = ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new
+      private_constant :FIBER_LOCK
+
       def lock_thread=(lock_thread) # :nodoc:
         @lock =
         case lock_thread
         when Thread
-          ActiveSupport::Concurrency::ThreadLoadInterlockAwareMonitor.new
+          THREAD_LOCK
         when Fiber
-          ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new
+          FIBER_LOCK
         else
           ActiveSupport::Concurrency::NullLock
         end