Re: (ITS#8281) Syncrepl refresh failure when slapd is restarted midstream

[michael@stroeder.com]

hyc@symas.com wrote:
> Michael Ströder wrote:
>> hyc@symas.com wrote:
>>> Generating a new contextCSN at startup is of questionable worth. We discussed
>>> this a bit 'way back in 2004
>>> http://www.openldap.org/lists/openldap-devel/200408/msg00035.html Perhaps we
>>> should just not do it;
>>
>> +1
>>
>>> if a single-master provider starts up empty and a
>>> consumer tries to talk to it and both have an empty cookie, the provider
>>> should just respond "you're up to date".
>>
>> Why not return an error to the consumer?
> 
> Typically if a consumer receives an error it will disconnect and retry later. 
> There's not much point making the consumer reconnect - which may be costly for 
> a TCP session. If it's a refreshAndPersist consumer, it just needs to hang on 
> and wait for some real data to arrive.

Is the cost really that high compared to the rest of the initialization?

>> Does the provider know whether it's running as single-master?
> 
> Generally yes. A single-master setup has serverID=0.

Hmm, this introduces more semantics on serverID. I have some doubts about
corner-cases.

Maybe I misunderstood but IMO the issue was about changing a provider to a MMR
replica which would need serverID!=0 anyway.

Ciao, Michael.