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Re: Antw: Re: contextCSN values and MMR

Ulrich Windl wrote:
>>>> Christian Kratzer <ck-lists@cksoft.de> schrieb am 10.08.2013 um 19:43 in
> Nachricht <alpine.BSF.2.00.1308101942120.18017@pohjola.cksoft.de>:
>> On Sat, 10 Aug 2013, Michael StrÃder wrote:
>>> Are contextCSN values on all replicas really in sync if changes were 
>> correctly
>>> replicated?
>>> I've implemented a monitoring check used with normal MMR setup (OpenLDAP
>>> 2.4.35, own build on Debian Squeeze) which also checks the contextCSN
> values
>>> on all replicas compared by server-id.
>>> Sometimes we observe, even in isolated tests, that contextCSN values for a
>>> certain server-id differ for quite a while (up to hours) even though the
>>> changes coming from that server were definitely replicated to all other
>>> replicas. After a while the contextCSN values get suddenly updated.
>>> Unfortunately this does not always happen.
>>> Any hint is highly appreciated.
>> I have always suspected that this is due to the specific setting of:
>>         syncprov-checkpoint <ops> <minutes>
>>                After a write operation has succeeded, write the contextCSN 
>> to the underlying database  if  <ops>  write
>>                operations  or more than <minutes> time have passed since the
>> last checkpoint. Checkpointing is disabled
>>                by default.
>> Not sure though.
> do you "query" by slapcat or by an LDAP search? For the former it's documented
> that contextCSN is updated lazily. For the latter I'm not sure.

Using slapcat in a monitoring check invoked every minute would be pretty dumb.
So of course I'm retrieving the contextCSN values from replicated DBs via LDAP.

Ciao, Michael.

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