diff options
Diffstat (limited to 'activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb')
| -rw-r--r-- | activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb | 80 |
1 files changed, 50 insertions, 30 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 2d62fd8d50..5ec2fc073e 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb @@ -69,7 +69,7 @@ module ActiveRecord # threads, which can occur if a programmer forgets to close a # connection at the end of a thread or a thread dies unexpectedly. # Regardless of this setting, the Reaper will be invoked before every - # blocking wait. (Default nil, which means don't schedule the Reaper). + # blocking wait. (Default +nil+, which means don't schedule the Reaper). # #-- # Synchronization policy: @@ -116,7 +116,7 @@ module ActiveRecord end end - # If +element+ is in the queue, remove and return it, or nil. + # If +element+ is in the queue, remove and return it, or +nil+. def delete(element) synchronize do @queue.delete(element) @@ -135,7 +135,7 @@ module ActiveRecord # If +timeout+ is not given, remove and return the head the # queue if the number of available elements is strictly # greater than the number of threads currently waiting (that - # is, don't jump ahead in line). Otherwise, return nil. + # is, don't jump ahead in line). Otherwise, return +nil+. # # If +timeout+ is given, block if there is no element # available, waiting up to +timeout+ seconds for an element to @@ -171,14 +171,14 @@ module ActiveRecord @queue.size > @num_waiting end - # Removes and returns the head of the queue if possible, or nil. + # Removes and returns the head of the queue if possible, or +nil+. def remove @queue.shift end # Remove and return the head the queue if the number of # available elements is strictly greater than the number of - # threads currently waiting. Otherwise, return nil. + # threads currently waiting. Otherwise, return +nil+. def no_wait_poll remove if can_remove_no_wait? end @@ -282,7 +282,7 @@ module ActiveRecord end # Every +frequency+ seconds, the reaper will call +reap+ on +pool+. - # A reaper instantiated with a nil frequency will never reap the + # A reaper instantiated with a +nil+ frequency will never reap the # connection pool. # # Configure the frequency by setting "reaping_frequency" in your @@ -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 @@ -349,8 +350,7 @@ module ActiveRecord # currently in the process of independently establishing connections to the DB. @now_connecting = 0 - # A boolean toggle that allows/disallows new connections. - @new_cons_enabled = true + @threads_blocking_new_connections = 0 @available = ConnectionLeasingQueue.new self end @@ -445,8 +445,6 @@ module ActiveRecord # connections in the pool within a timeout interval (default duration is # <tt>spec.config[:checkout_timeout] * 2</tt> seconds). def clear_reloadable_connections(raise_on_acquisition_timeout = true) - num_new_conns_required = 0 - with_exclusively_acquired_all_connections(raise_on_acquisition_timeout) do synchronize do @connections.each do |conn| @@ -457,24 +455,9 @@ module ActiveRecord conn.disconnect! if conn.requires_reloading? end @connections.delete_if(&:requires_reloading?) - @available.clear - - if @connections.size < @size - # because of the pruning done by this method, we might be running - # low on connections, while threads stuck in queue are helpless - # (not being able to establish new connections for themselves), - # see also more detailed explanation in +remove+ - num_new_conns_required = num_waiting_in_queue - @connections.size - end - - @connections.each do |conn| - @available.add conn - end end end - - bulk_make_new_connections(num_new_conns_required) if num_new_conns_required > 0 end # Clears the cache which maps classes and re-connects connections that @@ -581,6 +564,24 @@ 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 @@ -681,13 +682,32 @@ module ActiveRecord end def with_new_connections_blocked - previous_value = nil synchronize do - previous_value, @new_cons_enabled = @new_cons_enabled, false + @threads_blocking_new_connections += 1 end + yield ensure - synchronize { @new_cons_enabled = previous_value } + num_new_conns_required = 0 + + synchronize do + @threads_blocking_new_connections -= 1 + + if @threads_blocking_new_connections.zero? + @available.clear + + num_new_conns_required = num_waiting_in_queue + + @connections.each do |conn| + next if conn.in_use? + + @available.add conn + num_new_conns_required -= 1 + end + end + end + + bulk_make_new_connections(num_new_conns_required) if num_new_conns_required > 0 end # Acquire a connection by one of 1) immediately removing one @@ -739,7 +759,7 @@ module ActiveRecord # and increment @now_connecting, to prevent overstepping this pool's @size # constraint do_checkout = synchronize do - if @new_cons_enabled && (@connections.size + @now_connecting) < @size + if @threads_blocking_new_connections.zero? && (@connections.size + @now_connecting) < @size @now_connecting += 1 end end @@ -833,7 +853,7 @@ 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 |