Jan Wieck <JanWieck at Yahoo.com> writes:
> On 12/8/2007 12:52 PM, Peter Geoghegan wrote:
>> Hello,
>> I'm using slony to power a point-of-sale system - changes in the
>> back-office are replicated amongst tills (subscribers). For business
>> logic reasons, I'd like to be able to create a backlog of changes,
>> and then have the slon daemon replicate all such changes upon being
>> explicitly told to do so, rather then having the daemon
>> automatically replicate all changes to the replication set.
>> Is this possible? How so?
>
> Artificially delaying the replication process for purposes of point in
> time recovery was considered in the original design of the Slony-I
> system, but the mechanism was actually never implemented. The idea was
> not quite how you describe it above, where slon would wait until some
> sort of command kicks off the catch up process, but rather that slon
> would ignore events unless they are at least X minutes old. This could
> relatively simple be implemented in the query that looks for new
> events in the remote_listen thread, by adding a qualification that
> suppresses those "too new" events.
>
> I will see if we can easily add the feature to the upcoming 2.0
> release of Slony-I.

Actually, a form of this feature is already in 1.2.

Run "slon -h", and look at the "-l" flag, aka "lag_interval".
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