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From Kiran Ayyagari <kayyag...@apache.org>
Subject Re: Questions regarding Aliases
Date Tue, 24 Apr 2012 14:19:03 GMT
On Tue, Apr 24, 2012 at 4:58 PM, Emmanuel L├ęcharny <elecharny@gmail.com> wrote:
> Hi guys,
>
> Aliases handling is one of the biggest challenge in LDAP, as it imposes a
> lot of constraints. First of all, keep in mind that Alias support is not
> mandatory.
>
> Some of the problem we have when dealing with Alaises are :
> - cycle detection : we should not allow the creation of an alias that causes
> a cycle
> - duplicated entry removals in searches : we shuld not return an entry that
> has already been returned
> - unlinked aliases : when the aliased entry is removed, we should should
> handle it
> - subtree searches with aliases : we may have a very high nunber of entries
> to return
> - move operation : how do we handle the aliases modification when the
> aliased entries is move ?
> - cross-partitions aliases : how do we handle them ?
> - replication of aliases
>
> Right now, my concern is about duplicated entries removal and cycle
> detection, during a search processing :
>
> 1) Cycle detection :
> Should we assume that the cycles are detected during the alias creation ? Or
> should we detect it while processing the search ? (I'm nclined to think that
> cycle are forbidden during their creation)
>
> 2) duplicated entries removal
> I don't see any other way but storing a hash of all the UUID we already have
> transmitted, and to check when we have a new candidate if this candidate has
> already been processed. This is potentially *extremely* costly, if we have
> millions of entries (even if there is a size limit, which protects us from a
> OOM, because this size limit is not enforced for the manager user).
> Is there a better way ?
>
> 3) Current Aliases index
> I didn't have time to check what those index are used for, so if someone can
> give me a quick heads up, that would save me a few days of code diging...
>
this is used exactly for solving the above mentioned 'cycle detection' problem
> Many thanks !
>
> --
> Regards,
> Cordialement,
> Emmanuel L├ęcharny
> www.iktek.com
>



-- 
Kiran Ayyagari

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