Variable binding performance

[K0Te]

Hi,
I've profiled cx_oracle_on_ctypes on PyPy-2.6.1 with vprof profiler. vprof is a statistical profiler, so it shouldn't affect relative time, spent in different code parts.
Results show that for simple INSERT with 2 variables:

import cx_Oracle

conn = cx_Oracle.connect('user/pass@DB')
cr = conn.cursor()
sql = 'INSERT INTO TEST(num, chr) values(:num, :chr)'
for i in range(10**3):
    cr.execute(sql, {'num': i, 'chr': 'test_string'})
conn.commit()
cr.close()
conn.close()

68% of CPU time is spent on variable binding, and 27% is spent on execute().
Here are profiling results:

 100.0%  <module>                      t.py:1
 69.3%   execute                       cx_Oracle/cursor.py:265
 46.0%   set_bind_variables            cx_Oracle/cursor.py:160
 45.3%   set_bind_variable_helper      cx_Oracle/cursor.py:209
 43.9%   set_value                     cx_Oracle/variable.py:225
 43.5%   set_single_value              cx_Oracle/variable.py:237
 32.4%   __call__                      /usr/lib64/pypy-2.6.1/lib_pypy/_ctypes/function.py:710
 29.9%   <module>                      cx_Oracle/__init__.py:1
 26.5%   _call_funcptr                 /usr/lib64/pypy-2.6.1/lib_pypy/_ctypes/function.py:368
 20.7%   internal_execute              cx_Oracle/cursor.py:135
 20.1%   set_value                     cx_Oracle/numbervar.py:136
 19.8%   <module>                      cx_Oracle/custom_exceptions.py:1
 19.8%   <module>                      cx_Oracle/utils.py:1
 19.8%   <module>                      cx_Oracle/oci.py:1
 17.7%   set_value                     cx_Oracle/stringvar.py:98
 15.8%   set_value_from_integer        cx_Oracle/numbervar.py:232
 11.6%   <module>                      cx_Oracle/oci_generated_11.py:1
 8.9%    _as_ffi_pointer_              /usr/lib64/pypy-2.6.1/lib_pypy/_ctypes/pointer.py:125
 7.7%    <module>                      cx_Oracle/oci_generated_12.py:1
 7.2%    new_from_object               cx_Oracle/buffer.py:36
 7.0%    set_row_count                 cx_Oracle/cursor.py:354
 6.7%    OCIAttrGet                    cx_Oracle/pythonic_oci.py:7
 6.3%    load_library                  cx_Oracle/oci_generated_12.py:359
 6.3%    getpaths                      cx_Oracle/oci_generated_12.py:383
 6.3%    __setitem__                   /usr/lib64/pypy-2.6.1/lib_pypy/_ctypes/array.py:185
 6.2%    _compile                      /usr/lib64/pypy-2.6.1/lib-python/2.7/re.py:230
 6.2%    getplatformpaths              cx_Oracle/oci_generated_12.py:519
 6.2%    compile                       /usr/lib64/pypy-2.6.1/lib-python/2.7/re.py:192
 6.2%    compile                       /usr/lib64/pypy-2.6.1/lib-python/2.7/sre_compile.py:567
 5.4%    _create_ld_so_cache           cx_Oracle/oci_generated_12.py:457
 4.7%    glob                          /usr/lib64/pypy-2.6.1/lib-python/2.7/glob.py:18

I've checked code, however it is not clear if it is possible to improve variable binding performance.
Please advise.