[mythtv-users] Mooting architecture for a DataDirect replacement

[Jay R. Ashworth]

On Sun, Jun 24, 2007 at 03:31:22PM +1000, Peter Schachte wrote:
> > Date-Posted:
> > 
> > If they come in out of order, you can remember when the latest update
> > applied was posted and ignore the older one.
> 
> That only works if the second posting comes in before you apply the first; in
> general I expect you'd apply updates as soon as they arrive.  So you'd know
> when updates arrived out of order, but you wouldn't be able to fix it.  The
> best you could do is apply them out of order and hope there wasn't a conflict.

I think we're talking across one another.

If two updates come out that happen at different times, you're either
going to apply the second one second, because it has a later
Date-posted, or you're going to get the first one second, and ignore it
because it has an *earlier* date posted.

Perhaps I should have more clearly named the header: it's the UTC
timestamp at which the update packet was created.

> You could add a serial number header to each posting though, and hold back
> updates if one went missing, until the missing one arrived.  But then whenever
> a posting goes missing, your listings get frozen in their current state
> indefinitely (or at least for a couple of weeks).

Yup, and I don't want to go there.

I'm going to gin up a section on the wiki for this in a day or two, and
we'll have some space to play with failure cases, impact, and avoidance
techniques.

Cheers
-- jra
-- 
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