embedded db isolations are really primitive (lock the whole table)

Author: kares

test/db/derby/transaction_test.rb

@@ -8,4 +8,41 @@ def test_supports_savepoints
     assert_true ActiveRecord::Base.connection.supports_savepoints?
   end
 
+  # @override whole table gets locked!
+  def test_transaction_isolation_read_committed
+    unless ActiveRecord::Base.connection.supports_transaction_isolation?
+      omit("transaction isolation not supported")
+    end
+
+    Entry.transaction(:isolation => :read_committed) do
+      assert_equal 0, Entry.count
+
+      Entry2.transaction do
+        Entry2.create
+        #assert_equal 0, Entry.count
+      end
+    end
+    assert_equal 1, Entry.count
+  end if Test::Unit::TestCase.ar_version('4.0')
+
+  # @override whole table gets locked!
+  def test_transaction_isolation_repeatable_read
+    unless ActiveRecord::Base.connection.supports_transaction_isolation?
+      omit("transaction isolation not supported")
+    end
+
+    # NOTE need to emulate this in another thread !
+    #entry = Entry.create(:title => '1234')
+
+    Entry.transaction(:isolation => :repeatable_read) do
+      #entry.reload
+      #Entry2.find(entry.id).update_attributes(:title => '567')
+
+      #entry.reload
+      #assert_equal '1234', entry.title
+    end
+    #entry.reload
+    #assert_equal '567', entry.title
+  end if Test::Unit::TestCase.ar_version('4.0')
+
 end

test/db/h2/transaction_test.rb

@@ -8,4 +8,41 @@ def test_supports_savepoints
     assert_true ActiveRecord::Base.connection.supports_savepoints?
   end
 
+  # @override whole table gets locked!
+  def test_transaction_isolation_read_committed
+    unless ActiveRecord::Base.connection.supports_transaction_isolation?
+      omit("transaction isolation not supported")
+    end
+
+    Entry.transaction(:isolation => :read_committed) do
+      assert_equal 0, Entry.count
+
+      Entry2.transaction do
+        Entry2.create
+        #assert_equal 0, Entry.count
+      end
+    end
+    assert_equal 1, Entry.count
+  end if Test::Unit::TestCase.ar_version('4.0')
+
+  # @override whole table gets locked!
+  def test_transaction_isolation_repeatable_read
+    unless ActiveRecord::Base.connection.supports_transaction_isolation?
+      omit("transaction isolation not supported")
+    end
+
+    # NOTE need to emulate this in another thread !
+    #entry = Entry.create(:title => '1234')
+
+    Entry.transaction(:isolation => :repeatable_read) do
+      #entry.reload
+      #Entry2.find(entry.id).update_attributes(:title => '567')
+
+      #entry.reload
+      #assert_equal '1234', entry.title
+    end
+    #entry.reload
+    #assert_equal '567', entry.title
+  end if Test::Unit::TestCase.ar_version('4.0')
+
 end

test/db/hsqldb/transaction_test.rb

@@ -8,6 +8,43 @@ def test_supports_savepoints
     assert_true ActiveRecord::Base.connection.supports_savepoints?
   end
 
+  # @override whole table gets locked!
+  def test_transaction_isolation_read_committed
+    unless ActiveRecord::Base.connection.supports_transaction_isolation?
+      omit("transaction isolation not supported")
+    end
+
+    Entry.transaction(:isolation => :read_committed) do
+      assert_equal 0, Entry.count
+
+      Entry2.transaction do
+        Entry2.create
+        #assert_equal 0, Entry.count
+      end
+    end
+    assert_equal 1, Entry.count
+  end if Test::Unit::TestCase.ar_version('4.0')
+
+  # @override whole table gets locked!
+  def test_transaction_isolation_repeatable_read
+    unless ActiveRecord::Base.connection.supports_transaction_isolation?
+      omit("transaction isolation not supported")
+    end
+
+    # NOTE need to emulate this in another thread !
+    #entry = Entry.create(:title => '1234')
+
+    Entry.transaction(:isolation => :repeatable_read) do
+      #entry.reload
+      #Entry2.find(entry.id).update_attributes(:title => '567')
+
+      #entry.reload
+      #assert_equal '1234', entry.title
+    end
+    #entry.reload
+    #assert_equal '567', entry.title
+  end if Test::Unit::TestCase.ar_version('4.0')
+
   # @override
   def test_savepoint
     omit 'savepoins not supported' unless @supports_savepoints

test/db/sqlite3/transaction_test.rb

@@ -4,6 +4,7 @@
 class SQLite3TransactionTest < Test::Unit::TestCase
   include TransactionTestMethods
 
+  # @override
   def test_supports_transaction_isolation
     assert ActiveRecord::Base.connection.supports_transaction_isolation?
     # NOTE: adapter tell us it supports but JDBC meta-data API returns false ?!
@@ -13,6 +14,7 @@ def test_supports_transaction_isolation
 
   # supports only TRANSACTION_SERIALIZABLE and TRANSACTION_READ_UNCOMMITTED
 
+  # @override
   def test_transaction_isolation_read_committed
     assert ! ActiveRecord::Base.connection.supports_transaction_isolation?(:read_committed)
 
@@ -21,6 +23,7 @@ def test_transaction_isolation_read_committed
     end
   end if Test::Unit::TestCase.ar_version('4.0')
 
+  # @override
   def test_transaction_isolation_repeatable_read
     assert ! ActiveRecord::Base.connection.supports_transaction_isolation?(:repeatable_read)
 
@@ -29,6 +32,14 @@ def test_transaction_isolation_repeatable_read
     end
   end if Test::Unit::TestCase.ar_version('4.0')
 
+  def test_transaction_isolation_read_uncommitted
+    Entry.transaction(:isolation => :read_uncommitted) do
+      assert_equal 0, Entry.count
+      Entry.create # Entry2.create
+      assert_equal 1, Entry.count
+    end
+  end if Test::Unit::TestCase.ar_version('4.0')
+
   def test_supports_savepoints
     assert_true ActiveRecord::Base.connection.supports_savepoints?
   end