Merge pull request #119 from nuodb/vduda/DB-12019

[DB-12019] cursor.close() - fails to clear the result set with error thrown with NuoDB version >2.1

pynuodb/cursor.py

@@ -69,6 +69,8 @@ def close(self):
         """Closes the cursor into the database."""
         self._check_closed()
         self._statement_cache.shutdown()
+        if self._result_set:
+            self._result_set.close(self.session)
         self.closed = True
 
     def _check_closed(self):
@@ -79,10 +81,7 @@ def _check_closed(self):
             raise Error("connection is closed")
 
     def _reset(self):
-        """Resets SQL transaction variables.
-        
-        Also closes any open statements and result sets.
-        """
+        """Resets SQL transaction variables."""
         self.description = None
         self.rowcount = -1
         self.colcount = -1

pynuodb/encodedsession.py

@@ -271,6 +271,13 @@ def close_statement(self, statement):
         self._putMessageId(protocol.CLOSESTATEMENT).putInt(statement.handle)
         self._exchangeMessages(False)
 
+    def close_result_set(self, result_set):
+        """
+        :type result_set: ResultSet
+        """
+        self._putMessageId(protocol.CLOSERESULTSET).putInt(result_set.handle)
+        self._exchangeMessages(False)
+
     def create_prepared_statement(self, query):
         """
         :type query: str

pynuodb/result_set.py

@@ -35,3 +35,9 @@ def fetchone(self, session):
         res = self.results[self.results_idx]
         self.results_idx += 1
         return res
+
+    def close(self, session):
+        """
+        :type session EncodedSession
+        """
+        session.close_result_set(self)

tests/nuodb_cursor_test.py

@@ -3,7 +3,9 @@
 import unittest
 
 from .nuodb_base import NuoBase
-from pynuodb.exception import DataError, ProgrammingError, BatchError
+from pynuodb.exception import DataError, ProgrammingError, BatchError, OperationalError
+from distutils.version import LooseVersion
+from os import getenv
 
 
 class NuoDBCursorTest(NuoBase):
@@ -125,6 +127,29 @@ def test_executemany_somefail(self):
 
         cursor.execute("DROP TABLE executemany_table")
 
+    def test_result_set_gets_closed(self):
+        current_version = getenv('NUODB_VERSION', None) # skipif <2.1
+        if current_version is not None and not LooseVersion(current_version) < LooseVersion("2.1"):
+        # Server will throw error after 1000 open result sets
+            con = self._connect()
+            for j in [False, True]:
+                for i in range(2015):
+                    if not j:
+                        cursor = con.cursor()
+                        cursor.execute('select 1 from dual;')
+                        con.commit()
+                        cursor.close()
+                    else:
+                        if i >= 1000:
+                            with self.assertRaises(OperationalError):
+                                cursor = con.cursor()
+                                cursor.execute('select 1 from dual;')
+                                con.commit()
+                        else:
+                            cursor = con.cursor()
+                            cursor.execute('select 1 from dual;')
+                            con.commit()
+
 
 if __name__ == '__main__':
     unittest.main()