Bug #64394 Memory doesn't free after cursor close

• Submitted: 21 Feb 2012 10:34
• Modified: 24 Feb 2012 22:43
• Reporter: Geert Vanderkelen
• Status: Closed
• Category: Connector / Python
• Severity: S1 (Critical)
• Version: 0.3.2
• OS: Any
• Assigned to: Geert Vanderkelen
• CPU Architecture: Any

[21 Feb 2012 10:34] Geert Vanderkelen

Description:
Memory doesn't get freed or objects are not cleaned up by the automatic garbage collector at runtime.

How to repeat:
# The following is part of the unittests for creating the fix

class BugGarbage(tests.MySQLConnectorTests):
    def setUp(self):
        self.sample_size = 4
        self._reset_samples()
        gc.collect()
    
    def _reset_samples(self):
        self.samples = [0,] * self.sample_size
    
    def _assert_flat_line(self, samples):
        for i in range(0, len(samples)-1):
            try:
                if samples[i] != samples[i+1]:
                    self.fail("No flat-line for number of collected objects")
            except IndexError:
                pass # We are at the end.

    def test_cursor(self):
        config = self.getMySQLConfig()
        cnx = connection.MySQLConnection(**config)
        
        # Create a cursor and close using close()-method
        for i in range(0, self.sample_size):
            cursor = cnx.cursor()
            cursor.close()
            self.samples[i] = len(gc.get_objects())
        
        self._assert_flat_line(self.samples)
        
        self._reset_samples()
        # Create a cursor and rely on destructor to close
        for i in range(0, self.sample_size):
            cursor = cnx.cursor()
            self.samples[i] = len(gc.get_objects())
        
        self._assert_flat_line(self.samples)