RE: problem with modify using python-ldap

["Howard Chu" <hyc@highlandsun.com>]

The "Resource Unavailable" message means a system call failed with errno =
EAGAIN. In this case, ldap_read was trying to read from the connection and
there was no data available. Sounds like the python library isn't flushing
the entire LDAP request out to the network.

The fact that the behavior changes with debug level set to 1 is disturbing.
It sounds like some kind of race condition is involved, because there should
not be any ldap_read's occurring between the modify completing and sending
its result. You didn't specify which version of RedHat Linux you're using,
but I'd guess you're on 7.0 or 7.1 with a buggy threads library.

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc
  Symas: Premier OpenSource Development and Support

> -----Original Message-----
> From: owner-openldap-software@OpenLDAP.org
> [mailto:owner-openldap-software@OpenLDAP.org]On Behalf Of Allan Streib

> Using python-ldap-python-ldap-2.0.0pre04 with Python 2.2.1, and OpenLDAP
> 2.0.23 on RedHat Linux.
>
> Deleting and adding an attribute is taking 9 seconds.  The same actions
> using ldapmodify(1) on the command line complete virtually instantly.
>
> Oddly, the behavior does not manifest if log level 1 (trace function
> calls) is enabled.  Here is a log snip at level 6 (heavy trace debugging
> plus debug packet handling).  This first snip is with ldapmodify(1) as the
> client:
>
>     do_modify: dn (iuEduUPID=9900000004,ou=people,dc=iu,dc=edu)
>     modifications:
>             delete: iuEduMailDeliveryTo
>             add: iuEduMailDeliveryTo
>     ldbm_back_modify:
>     ldbm_modify_internal: delete
>     removing entire attribute iuEduMailDeliveryTo
>     ldbm_modify_internal: add
>     ldbm_modify_internal: replace
>     ldbm_modify_internal: replace
>     send_ldap_result: 0::
>
> Now with python-ldap's modify_s operation as the client:
>
>     do_modify: dn (iuEduUPID=9900000004,ou=people,dc=iu,dc=edu)
>     modifications:
>             delete: iuEduMailDeliveryTo
>             add: iuEduMailDeliveryTo
>     ldbm_back_modify:
>     ldbm_modify_internal: delete
>     removing entire attribute iuEduMailDeliveryTo
>     ldbm_modify_internal: add
>     ldbm_modify_internal: replace
>     ldbm_modify_internal: replace
>     ldap_read: want=1 error=Resource temporarily unavailable
>  **** hangs for about 9 seconds here ****
>     send_ldap_result: 0::
>
> Ultimately the modifications succeed.  The difference I see is that
> "Resource temporarily unavailable" message -- what is that resource?
>
> Any ideas for further troubleshooting?
>
> Thanks,
>
> Allan
>