Re: (ITS#5354) slapd repeatedly hangs and stops reponding

[orenl@cs.columbia.edu]

Pierangelo Masarati wrote:
> hyc@symas.com wrote:
>> Oren Laadan wrote:
>>>> It shows enough; back-meta is hanging waiting for responses from some other
>>>> LDAP server. This is a pretty bad configuration; you should not use back-meta
>>>> (or back-ldap) to redirect queries back into the same slapd. You should use
>>>> back-relay instead.
>>> I'm not quite sure why having the server query itself is such a bad idea.
>>> Can you please explain ?
>> Any request then occupies a minimum of two slapd threads - one for back-meta 
>> itself, and one for the extra inbound query. If you misconfigure the meta URIs 
>> then you get into an infinite loop, which consumes all of the available slapd 
>> threads.
> 
> Let me add that, moreover, any request is re-encoded as an LDAP request,
> sent to itself, re-decoded and re-processed by slapd.  Back-relay
> directly relies the original, decoded request to another database,
> within the same thread.  So it saves at least 3 resource-consuming steps-
> 

Ok, I see the rational. So I guess my question is whether back-relay gives
the same functionality like ldap-meta (that is, merging the two databases,
the remote one and the local one) except better with respect to a local
database ?  and if so, then how would I set it up for this ?

I looked at "subordinate" directive but I'm not sure it helps, since as
far as I could tell it can join two disjoint subtrees into seemingly one
big database. However, what I need is to add local (new) entries (not
only modify attributes) to an existing database.

Thanks,

Oren.


> p.
> 
> 
> 
> Ing. Pierangelo Masarati
> OpenLDAP Core Team
> 
> SysNet s.r.l.
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