require "cases/helper" require 'active_support/concurrency/latch' module ActiveRecord module ConnectionAdapters class ConnectionPoolTest < ActiveRecord::TestCase attr_reader :pool def setup super # Keep a duplicate pool so we do not bother others @pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec if in_memory_db? # Separate connections to an in-memory database create an entirely new database, # with an empty schema etc, so we just stub out this schema on the fly. @pool.with_connection do |connection| connection.create_table :posts do |t| t.integer :cololumn end end end end teardown do @pool.disconnect! end def active_connections(pool) pool.connections.find_all(&:in_use?) end def test_checkout_after_close connection = pool.connection assert connection.in_use? connection.close assert !connection.in_use? assert pool.connection.in_use? end def test_released_connection_moves_between_threads thread_conn = nil Thread.new { pool.with_connection do |conn| thread_conn = conn end }.join assert thread_conn Thread.new { pool.with_connection do |conn| assert_equal thread_conn, conn end }.join end def test_with_connection assert_equal 0, active_connections(pool).size main_thread = pool.connection assert_equal 1, active_connections(pool).size Thread.new { pool.with_connection do |conn| assert conn assert_equal 2, active_connections(pool).size end assert_equal 1, active_connections(pool).size }.join main_thread.close assert_equal 0, active_connections(pool).size end def test_active_connection_in_use assert !pool.active_connection? main_thread = pool.connection assert pool.active_connection? main_thread.close assert !pool.active_connection? end def test_full_pool_exception @pool.size.times { @pool.checkout } assert_raises(ConnectionTimeoutError) do @pool.checkout end end def test_full_pool_blocks cs = @pool.size.times.map { @pool.checkout } t = Thread.new { @pool.checkout } # make sure our thread is in the timeout section Thread.pass until t.status == "sleep" connection = cs.first connection.close assert_equal connection, t.join.value end def test_removing_releases_latch cs = @pool.size.times.map { @pool.checkout } t = Thread.new { @pool.checkout } # make sure our thread is in the timeout section Thread.pass until t.status == "sleep" connection = cs.first @pool.remove connection assert_respond_to t.join.value, :execute connection.close end def test_reap_and_active @pool.checkout @pool.checkout @pool.checkout connections = @pool.connections.dup @pool.reap assert_equal connections.length, @pool.connections.length end def test_reap_inactive ready = ActiveSupport::Concurrency::Latch.new @pool.checkout child = Thread.new do @pool.checkout @pool.checkout ready.release Thread.stop end ready.await assert_equal 3, active_connections(@pool).size child.terminate child.join @pool.reap assert_equal 1, active_connections(@pool).size ensure @pool.connections.each(&:close) end def test_remove_connection conn = @pool.checkout assert conn.in_use? length = @pool.connections.length @pool.remove conn assert conn.in_use? assert_equal(length - 1, @pool.connections.length) ensure conn.close end def test_remove_connection_for_thread conn = @pool.connection @pool.remove conn assert_not_equal(conn, @pool.connection) ensure conn.close if conn end def test_active_connection? assert !@pool.active_connection? assert @pool.connection assert @pool.active_connection? @pool.release_connection assert !@pool.active_connection? end def test_checkout_behaviour pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec connection = pool.connection assert_not_nil connection threads = [] 4.times do |i| threads << Thread.new(i) do connection = pool.connection assert_not_nil connection connection.close end end threads.each(&:join) Thread.new do assert pool.connection pool.connection.close end.join end # The connection pool is "fair" if threads waiting for # connections receive them in the order in which they began # waiting. This ensures that we don't timeout one HTTP request # even while well under capacity in a multi-threaded environment # such as a Java servlet container. # # We don't need strict fairness: if two connections become # available at the same time, it's fine if two threads that were # waiting acquire the connections out of order. # # Thus this test prepares waiting threads and then trickles in # available connections slowly, ensuring the wakeup order is # correct in this case. def test_checkout_fairness @pool.instance_variable_set(:@size, 10) expected = (1..@pool.size).to_a.freeze # check out all connections so our threads start out waiting conns = expected.map { @pool.checkout } mutex = Mutex.new order = [] errors = [] threads = expected.map do |i| t = Thread.new { begin @pool.checkout # never checked back in mutex.synchronize { order << i } rescue => e mutex.synchronize { errors << e } end } Thread.pass until t.status == "sleep" t end # this should wake up the waiting threads one by one in order conns.each { |conn| @pool.checkin(conn); sleep 0.1 } threads.each(&:join) raise errors.first if errors.any? assert_equal(expected, order) end # As mentioned in #test_checkout_fairness, we don't care about # strict fairness. This test creates two groups of threads: # group1 whose members all start waiting before any thread in # group2. Enough connections are checked in to wakeup all # group1 threads, and the fact that only group1 and no group2 # threads acquired a connection is enforced. def test_checkout_fairness_by_group @pool.instance_variable_set(:@size, 10) # take all the connections conns = (1..10).map { @pool.checkout } mutex = Mutex.new successes = [] # threads that successfully got a connection errors = [] make_thread = proc do |i| t = Thread.new { begin @pool.checkout # never checked back in mutex.synchronize { successes << i } rescue => e mutex.synchronize { errors << e } end } Thread.pass until t.status == "sleep" t end # all group1 threads start waiting before any in group2 group1 = (1..5).map(&make_thread) group2 = (6..10).map(&make_thread) # checkin n connections back to the pool checkin = proc do |n| n.times do c = conns.pop @pool.checkin(c) end end checkin.call(group1.size) # should wake up all group1 loop do sleep 0.1 break if mutex.synchronize { (successes.size + errors.size) == group1.size } end winners = mutex.synchronize { successes.dup } checkin.call(group2.size) # should wake up everyone remaining group1.each(&:join) group2.each(&:join) assert_equal((1..group1.size).to_a, winners.sort) if errors.any? raise errors.first end end def test_automatic_reconnect= pool = ConnectionPool.new ActiveRecord::Base.connection_pool.spec assert pool.automatic_reconnect assert pool.connection pool.disconnect! assert pool.connection pool.disconnect! pool.automatic_reconnect = false assert_raises(ConnectionNotEstablished) do pool.connection end assert_raises(ConnectionNotEstablished) do pool.with_connection end end def test_pool_sets_connection_visitor assert @pool.connection.visitor.is_a?(Arel::Visitors::ToSql) end # make sure exceptions are thrown when establish_connection # is called with an anonymous class def test_anonymous_class_exception anonymous = Class.new(ActiveRecord::Base) handler = ActiveRecord::Base.connection_handler assert_raises(RuntimeError) { handler.establish_connection anonymous, nil } end end end end