add deadlock test

test/deadlock_test.rb

@@ -0,0 +1,125 @@
+require File.dirname(__FILE__) + '/test_helper'
+
+DIR = '/tmp/bdb_deadlock_test'
+Bdb::Environment.config :path => DIR, :cache_size => 1 * 1024 * 1024, :page_size => 512
+
+class DeadlockTest < Test::Unit::TestCase
+  def setup
+    FileUtils.rmtree DIR
+    FileUtils.mkdir  DIR
+    Bdb::Environment[DIR].close      
+    @db = Bdb::Database.new('foo')
+  end
+
+  attr_reader :db
+
+  N = 5000 # total number of records
+  R = 10   # number of readers
+  W = 10   # number of writers
+  T = 20   # reads per transaction
+  L = 100  # logging frequency
+
+  def test_detect_deadlock
+    pids = []
+
+    W.times do |n|
+      pids << fork(&writer)
+    end
+
+    sleep(1)
+
+    R.times do
+      pids << fork(&reader)
+    end
+
+    # Make sure that all processes finish with no errors.
+    pids.each do |pid|
+      Process.wait(pid)
+      assert_equal status, $?.exitstatus
+    end
+  end
+
+  C = 10
+  def test_detect_unclosed_resources
+    threads = []
+
+    threads << Thread.new do
+      C.times do
+        sleep(10)
+
+        pid = fork do
+          cursor = db.db.cursor(nil, 0)
+          cursor.get(nil, nil, Bdb::DB_FIRST)
+          exit!(1)
+        end
+        puts "\n====simulating exit with unclosed resources ===="
+        Process.wait(pid)
+        assert_equal 1, $?.exitstatus
+      end
+    end
+
+    threads << Thread.new do
+      C.times do
+        pid = fork(&writer(1000))
+        Process.wait(pid)
+        assert [0,9].include?($?.exitstatus)
+      end
+    end
+
+    sleep(3)
+
+    threads << Thread.new do
+      C.times do
+        pid = fork(&reader(1000))
+        Process.wait(pid)
+        assert [0,9].include?($?.exitstatus)
+      end
+    end
+    
+    threads.each {|t| t.join}
+  end
+
+  def reader(n = N)
+    lambda do
+      T.times do
+        (1...n).to_a.shuffle.each_slice(T) do |ids|
+          db.transaction do
+            ids.each {|id| db.get(id)}
+          end
+          log('r')
+        end
+      end
+      db.close_environment
+    end
+  end
+
+  def writer(n = N)
+    lambda do
+      (1...n).to_a.shuffle.each do |id|
+        db.transaction do
+          begin
+            db.set(id, {:bar => "bar" * 1000 + " ayn #{rand}"})
+          rescue Bdb::DbError => e
+            if e.code == Bdb::DB_KEYEXIST
+              db.delete(id)
+              retry
+            else
+              raise(e)
+            end
+          end
+        end
+        log('w')
+      end
+      db.close_environment
+    end
+  end
+
+  def log(action)
+    @count ||= Hash.new(0)
+    if @count[action] % L == 0
+      print action.to_s
+      $stdout.flush
+    end
+    @count[action] += 1
+  end
+end