Re: [9fans] silly replica question (repeated m msgs won't go away)

Re: [9fans] silly replica question (repeated m msgs won't go away)

[Charles Forsyth]

i don't think i'd describe what replica attempts as `heuristic'.
there's a little graph of possibilities and it either chooses the safe
path or requests guidance.

an SHA1 hash would be helpful; by using mtime+length it can moan about
insignificant changes but then again, with some things it's possible
the mtime matters, and perhaps it should moan.

having mentioned SHA1: there might be an interesting variant that uses
venti scores.

Re: [9fans] silly replica question (repeated m msgs won't go away)

[Lucio De Re]

On Tue, Feb 10, 2004 at 04:10:20PM +0000, Charles Forsyth wrote:
>
> i don't think i'd describe what replica attempts as `heuristic'.
> there's a little graph of possibilities and it either chooses the safe
> path or requests guidance.
>
I really hope I don't sound confrontational, there's much I don't
know and can only guess at, but there's definitely more than a
trivial amount of slipperiness about replica that makes it unsuitable
for the type of replication that Microsoft used (or used to use)
to propagate changes to the users database between the PDC and BDCs
(if you don't know the acronym, you're missing nothing) or what
Lotus Notes uses (this is NetNews in disguise or is it on steroids?)
or, for that matter, the OpenLDAP replicator.

> an SHA1 hash would be helpful; by using mtime+length it can moan about
> insignificant changes but then again, with some things it's possible
> the mtime matters, and perhaps it should moan.
>
I think there's a philosophy behind replica that suggests humans
are involved therefore there's scope for some fuzzy logic.  I'm
not even arguing the merits thereof, it's a perfectly good approach.
What I prefer, however, is the solidity of the dump and a tool to
extract the updates list in a format that makes it possible to
revert them and/or apply them elsewhere.

I'd better be careful, however, I'm beginning to recognise signs
that my attraction for CVS is coming through.

> having mentioned SHA1: there might be an interesting variant that uses
> venti scores.

I won't try to follow your thinking there, it's way beyond my
processing powers :-)

++L

[9fans] to andrey

[rog]

to mirtchov@cpsc.ucalgary.ca:

i've tried to send you a couple of email messages, which
you don't appear to have got.

email me if you haven't and i'll try some other way.