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Re: (ITS#3939) min/max function extension to LDAP protocol

--On Tuesday, August 16, 2005 11:58 AM -0700 Quanah Gibson-Mount 
<quanah@stanford.edu> wrote:

> --On Tuesday, August 16, 2005 11:53 AM -0700 "Kurt D. Zeilenga"
> <Kurt@OpenLDAP.org> wrote:
>> LDAP already provides a mechanism for performing this function,
>> by use of the paging (1 page of 1 entry) [RFC2696] and sorting
>> [RFC2891] controls.  Of course, slapd(8) does not support the
>> sorting control.
>> Given this is (or can be assumed to be) a request for enhancement
>> to OpenLDAP Software and not a request to enhance LDAP (if the
>> latter, the OpenLDAP ITS is not the right place to request
>> enhancements to LDAP be made), I suggest this ITS be regarded
>> as a request to implement the sorting control.
> Yes, this is a request to enhance OpenLDAP appropriately. :)

Actually, after talking to Howard, I believe the above controls aren't 
sufficient.  The whole problem is candidate generation.  Now, with BDB, it 
should be possible to get the min and max values from the first and last 
marker in the entryCSN index database, since it can only be indexed with 
equality.  So for syncrepl to ever really be efficient for servers that are 
stopping/starting after deletes or multiple modifies to the same entry, it 
needs a way to get those values.  This completely avoids any candidate 
generation, and allows the syncprovider to quickly let the replica know if 
its CSN is out of date.  How one would implement that inside the LDAP specs 
is a different issue. ;)


Quanah Gibson-Mount
Principal Software Developer
ITSS/Shared Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html

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