Re: commit: ldap/tests/scripts defines.sh test035-meta test036-meta-concurrency

[Pierangelo Masarati <ando@sys-net.it>]

Pierangelo Masarati wrote:

> The bad news is that under some circumstances back-meta still happens 
> to hang waiting for a result from a target that is not willing to send 
> any.  I've worked it around by re-issuing the anonymous bind exactly 
> once after the configured retries on ldap_result() have been attempted 
> unsuccessfully.  Unfortunately this occurs so  few times and under so 
> heavy load that first of all it's unrealistic, and it's pretty 
> difficult to track.  In fact, in these cases I can easily attach the 
> back-meta with gdb and see it retry indefinitely, but there's no clue 
> in attaching the remote server, because that has anything to do with 
> the operation, and its logs don't say anything about the problem.  The 
> libldap is waiting on a message that'll never come.  So re-issuing the 
> operation seems to be the right approach.

I think I've spotted the cause.  I was doing something that could be 
interesting, but right now seems inappropriate, and it is having some 
undesired side effect.  When doing reads, what's needed is a unique 
target, holding the search base.  If none cannot be identified by 
looking at the target's naming contexts, an internal search is 
performed, using the request DN as base, and a sizelimit of 1.  If 
exactly one target is found, it is used; otherwise, an error is returned 
because no exact base can be selected.  I might need to tweak this a 
bit, but that's how it works.  The point is that meta_back_search(), in 
case of a match when the scope is BASE, was actually returing result and 
abandoning the other operations.  This, and I don't know why, could 
result in the abandoned targets refuse to respond to the anonymous bind 
immediately after the abandon.  Currently I have no clue.  For other 
reasons, i turned that feature off, and now that abandons don't occur 
any longer, the problem doesn't show up any more.

p.

--
Pierangelo Masarati
mailto:pierangelo.masarati@sys-net.it



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