- rework Oracle to no longer do its own unicode conversion; this has been observed

to be very slow.  this now has the effect of producing "conditional" unicode
conversion for the Oracle backend, as it still returns NVARCHAR etc. as unicode
[ticket:2911]
- add new "conditional" functionality to unicode processors; the C-level
function now uses PyUnicode_Check() as a fast alternative to the isinstance()
check in Python

1 files changed, 4 insertions, 13 deletions

diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py
index 702e77360..0cc90f26b 100644
--- a/lib/sqlalchemy/sql/sqltypes.py
+++ b/lib/sqlalchemy/sql/sqltypes.py
@@ -204,20 +204,11 @@ class String(Concatenable, TypeEngine):
                                     dialect.encoding, self.unicode_error)
 
             if needs_isinstance:
-                # we wouldn't be here unless convert_unicode='force'
-                # was specified, or the driver has erratic unicode-returning
-                # habits.  since we will be getting back unicode
-                # in most cases, we check for it (decode will fail).
-                def process(value):
-                    if isinstance(value, util.text_type):
-                        return value
-                    else:
-                        return to_unicode(value)
-                return process
+                return processors.to_conditional_unicode_processor_factory(
+                                    dialect.encoding, self.unicode_error)
             else:
-                # here, we assume that the object is not unicode,
-                # avoiding expensive isinstance() check.
-                return to_unicode
+                return processors.to_unicode_processor_factory(
+                                    dialect.encoding, self.unicode_error)
         else:
             return None