"import" creates GIL overhead every time it is run. For threaded MySQLdb apps,

it doesn't make sense to pay that cost for every execute(), so lets move some
of these imports.

http://wiki.python.org/moin/PythonSpeed/PerformanceTips#ImportStatementOverhead

MySQLdb/MySQLdb/cursors.py

@@ -6,6 +6,9 @@ default, MySQLdb uses the Cursor class.
 """
 
 import re
+import sys
+from types import ListType, TupleType, UnicodeType
+
 
 restr = (r"\svalues\s*"
         r"(\(((?<!\\)'[^\)]*?\)[^\)]*(?<!\\)?'"
@@ -65,7 +68,7 @@ class BaseCursor(object):
         self.close()
         self.errorhandler = None
         self._result = None
-        
+
     def close(self):
         """Close the cursor. No further queries will be possible."""
         if not self.connection: return
@@ -147,8 +150,6 @@ class BaseCursor(object):
         Returns long integer rows affected, if any
 
         """
-        from types import ListType, TupleType
-        from sys import exc_info
         del self.messages[:]
         db = self._get_db()
         charset = db.character_set_name()
@@ -167,7 +168,7 @@ class BaseCursor(object):
                 self.messages.append((TypeError, m))
                 self.errorhandler(self, TypeError, m)
         except:
-            exc, value, tb = exc_info()
+            exc, value, tb = sys.exc_info()
             del tb
             self.messages.append((exc, value))
             self.errorhandler(self, exc, value)
@@ -216,8 +217,7 @@ class BaseCursor(object):
             else:
                 self.errorhandler(self, TypeError, msg)
         except:
-            from sys import exc_info
-            exc, value, tb = exc_info()
+            exc, value, tb = sys.exc_info()
             del tb
             self.errorhandler(self, exc, value)
         r = self._query('\n'.join([query[:p], ',\n'.join(q), query[e:]]))
@@ -254,7 +254,6 @@ class BaseCursor(object):
         disconnected.
         """
 
-        from types import UnicodeType
         db = self._get_db()
         charset = db.character_set_name()
         for index, arg in enumerate(args):