Speed difference, which version to use?

[Michael Ströder]

Anders Karlsson wrote:
> 
> Since it was built for Python 1.x I upgraded to Python-LDAP 2.0.0pre04
> which worked fine, but considerable slower that the old version. A python
> program that changed some posts in the LDAP database and did two searches
> took about five seconds with 2.0.0pre04, compared to less than a second
> with 1.10alpha3.
> 
> Why is there such big speed difference?

Hmm, there might be different issues here:

1. I changed the implementation of the synchronous methods *_s() 
to avoid getting blocked in OpenLDAP 2 _s() functions. Especially 
there's a reimplementation of result() in 
ldap.ldapobject.LDAPObject which does the timeout handling itself. 
The main reason is that the OpenLDAP libs are not thread-safe and 
therefore a module-wide lock is used to serialize all calls into 
the OpenLDAP libs.
(If someone manages to use OpenLDAP 2.1's libldap_r instead of 
libldap this might help to reduce some of the locking.)

2. You might also have upgraded the LDAP server to OpenLDAP 2 
(which does stricter checking) or changed the indexing 
configuration (which is a performance penalty when writing)?

3. The OpenLDAP 2.x libs are slower. (python-ldap 1.x was linked 
against OpenLDAP 1.x libs.)

Now for 1. issue:

You could try a very simple result() implementation (tweak 
Lib/ldap/ldapobject.py):

   def result(self,msgid=_ldap.RES_ANY,all=1,timeout=-1):
     return self._ldap_call(self._l.result,msgid,all,timeout)

I did some testing with this method implementation for measuring 
the overhead of my non-blocking version. I read the RootDSE of 
Netscape DS 4.16SP1 running on the same box. (Solely searching the 
RootDSE is an appropriate method to eliminate the influence of 
database backends and such.)
On average it seems to be approx. 65% faster to use this simple 
method above. This is something to consider.

Hmm, but you are experiencing a performance difference which is 
much higher (5 times slower as I understand your posting). I'd 
really appreciate if you could send more information about your 
environment and *all* the changes you did. Performance measurement 
numbers done under really the same conditions are also appreciated 
off course.

Ciao, Michael.