Revert "backport fair connection pool 02b2335563 to 3-2-stable"

This reverts commit 0693e079708a52b777f2b7872b8e3d467b880a0d.

Revert "Cache columns metadata to avoid extra while testing"

This reverts commit a82f1e3f5d11c8dfba9f4c911745ec40a7965216.

Reason: This is causing failures in the postgresql build.
See http://travis-ci.org/#!/rails/rails/builds/2485584

Related with #7675

1 files changed, 0 insertions, 104 deletions

diff --git a/activerecord/test/cases/connection_pool_test.rb b/activerecord/test/cases/connection_pool_test.rb
index 2ada2c1fe1..5cecfa90e7 100644
--- a/activerecord/test/cases/connection_pool_test.rb
+++ b/activerecord/test/cases/connection_pool_test.rb
@@ -128,110 +128,6 @@ module ActiveRecord
 
       end
 
-      # The connection pool is "fair" if threads waiting for
-      # connections receive them 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 of 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 # connection return value 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 # connection return value 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