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Re: Syncrepl and chain Overlay

[moved from -software to -devel]

>> mmmmh, that global overlay stuff needs some review; I mean, for write
>> operations I suspect some of the data consolidation should occur earlier
>> so that regular overlays can be injected as global.
> Ok I didn't know that, thanks for clarifying.

Note that I'm mostly concerned about write operations.

>> I'v ebeen playing with the chain overlay recently (see my fixes this
>> week)
>> and it worked well alone.  There might be some isses in cooperating with
>> the syncrepl.  Did you try reversing the overlay stacking order?
> I am not using any other overlays than chain. I might be wrong here but
> isn't
> the syncprov overlay only needed on the provider side?


> Anyway, I've removed all the syncrepl related stuff from my config and
> inserted a normal referral into the database. With that the chain overlay
> seems to work fine. So seems to be indeed some integration issue with
> syncrepl.

The chain overlay responds when the server is __returning__ a referral, so
there shouldn't be any interaction with syncrepl.  I suspect there might
be some if syncrepl registers any callback that by chance call the whole
stack instead of directly the underlying database.

In any case, what I note is that the syncrepl consumer (without chain),
when it finds a reference in the subtree it's shadowing (at least in
refreshOnly the first time it imports the provider) it (erroneously, I
assume) chases it, so it ends up shadowing both providers (I'm playing
with a scenario where two providers host two halves of a tree, with
cross-referrals for the other half).

I'll investigate this further.


Pierangelo Masarati

    SysNet - via Dossi,8 27100 Pavia Tel: +390382573859 Fax: +390382476497