Databases Synchronization Proposal
RIPE Database Manager
Fri Mar 3 16:34:20 CET 1995
Dear Laurent, > > There is semantic information in the order in which updates are processed. > > Assume the following scenario: > > 1. Someone registers a Bananna object (note typo) > > 2. The database includes & sends ack > > 3. The person finds the typo > > 4. The person deletes Bananna > > 5. The person registers Banana (no typo). > > > > If these updates are also sent to a shadow copy, then one must make > > shure that (1) comes before (4), otherwise the delete won't work > > and Bananna will still be in (the databases will be out of sync) > > I don't get it. If the update is time stamped (as specified in my > prososal) with 1 second resolution, then ordering of the update is > trivial. If (1) come after (4) then it'll be rejected because it's older. > > As for the lost mail and desynchronisation problem, the FTP > once in the while should solve the problem (as pointed out by Daniel). But what happens if you don't receive 5 or 1 ? Time stamps are not unique. Why not use a unique serial number ? That means you can track down when you missed any E-mails. As Geert Jan explained it is vital to do the updates in the right order. You can't check this with a time stamp since you don't know if you missed any E-mail. Kind regards, David Kessens RIPE NCC Database maintainer -------- Logged at Fri Mar 3 21:34:27 MET 1995 ---------
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