On 12/1/2008 9:54 PM, Troy Wolf wrote:
> Thanks for the reply, Jan!
> 
> On Mon, Dec 1, 2008 at 4:29 PM, Jan Wieck <JanWieck at yahoo.com> wrote:
>> Well, it certainly is a bug that it continues to generate logs ... we will
>> see to fix it and stop it from creating useless files.
>>
> 
> So you confirm the 14.2 documentation is incorrect. That part will be
> easy to fix at least! :)
> 
>> The reason is the same as for not being able to create such a setup in the
>> first place. Log shipping is implemented as a byproduct of the normal
>> replication process done by a subscriber. That includes keeping track of
>> what has been replicated thus far.
> 
> I say this with limited knowledge of how Slony works under the hood,
> but it seems obvious that the Slony origin knows about all the changes
> because it communicates them to the subscriber, right? In any case,
> yes, the ability to generate log files directly from the origin would
> be useful to people I think.

The information is all there, that much is true.

The original idea was to create a separate process that "acts" like 
another node based on a "spool node", which the origin never connects 
to. That separate process would then write those logs.

> Can you speak to Slony II and it's Log Shipping capabilities? Is Log
> Shipping improved, enhanced, or otherwise in version 2?

Some of the required infrastructure changes for that "spool node" had 
been done about four years ago already. But nobody ever felt the need to 
actually implement it.

I totally see and agree that this is useful for people. But apparently 
it is not useful enough to cause someone look for a developer, get it 
done and contribute a patch. So while there have been minor improvements 
in the log shipping code for version 2.0, this big change is still not 
done. This is supposed to be a community project, so if someone needs 
this functionality, we are certainly willing to include it into the code 
base. "Include" it, not "develop" it.


Jan

-- 
Anyone who trades liberty for security deserves neither
liberty nor security. -- Benjamin Franklin