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Re: Replication delay



On 3/22/19 8:41 PM, Quanah Gibson-Mount wrote:
> --On Friday, March 22, 2019 8:35 PM +0100 Michael Ströder
> <michael@stroeder.com> wrote:
> 
>> See also my response. It's the usual monitoring-shows-contextCSN-diff
>> while replication just works. It's a bug I'm observing for years now.
> 
> It's not a bug.
> 
>      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.

Does that really mean that contextCSN value retrieved via LDAP are not
current? This would also break replication.

Up to now I understood that this option is similar to slapd-mdb's
checkpoint directive. Which means, the data retrieved via LDAP is
current but the DB files might not be fsynced yet.

Also in Æ-DIR the default is:

syncprov-checkpoint 1000 2

So according to the man-page you cited it means the gap must not be
greater than two minutes. But it's sometimes several hours and it lasts
for hours even if you write again something.

IMO it's simply a bug.

Ciao, Michael.