1 files changed, 20 insertions, 1 deletions
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 fa2f685e43..e6b6b60c1b 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -307,6 +307,7 @@ module ActiveRecord
       end
 
       include MonitorMixin
+      include QueryCache::ConnectionPoolConfiguration
 
       attr_accessor :automatic_reconnect, :checkout_timeout, :schema_cache
       attr_reader :spec, :connections, :size, :reaper
@@ -581,6 +582,24 @@ module ActiveRecord
         @available.num_waiting
       end
 
+      # Return connection pool's usage statistic
+      # Example:
+      #
+      #    ActiveRecord::Base.connection_pool.stat # => { size: 15, connections: 1, busy: 1, dead: 0, idle: 0, waiting: 0, checkout_timeout: 5 }
+      def stat
+        synchronize do
+          {
+            size: size,
+            connections: @connections.size,
+            busy: @connections.count { |c| c.in_use? && c.owner.alive? },
+            dead: @connections.count { |c| c.in_use? && !c.owner.alive? },
+            idle: @connections.count { |c| !c.in_use? },
+            waiting: num_waiting_in_queue,
+            checkout_timeout: checkout_timeout
+          }
+        end
+      end
+
       private
         #--
         # this is unfortunately not concurrent
@@ -833,7 +852,7 @@ module ActiveRecord
     class ConnectionHandler
       def initialize
         # These caches are keyed by spec.name (ConnectionSpecification#name).
-        @owner_to_pool = Concurrent::Map.new(initial_capacity: 2) do |h,k|
+        @owner_to_pool = Concurrent::Map.new(initial_capacity: 2) do |h, k|
           h[k] = Concurrent::Map.new(initial_capacity: 2)
         end
       end