replication on the fly?

Hi,

Can replication not be done on-the-fly?

Why is it necessary for the master to go offline and then do the
replication? Is it not possible to have a system where a write to one
immediately triggers a write to all the others?
Maybe if a server wants to write to a table it sends out a 'lock
table' message to all the others, then does its write and sends the
change to the others, and then unlocks the table after everybody have
written the change.

Like in a clustered web-server, how do I gurantee uptime if using
replication? I can't go offline everytime there is a write to the db.
Is the only solution to have the DB on a network FS?

Thanks, cheers,
Tobias

<nsa.usa@gmail.com> wrote in message
news:1185437593.374511.39370@w3g2000hsg.googlegrou ps.com...
> Hi,
>
> Can replication not be done on-the-fly?
>
> Why is it necessary for the master to go offline and then do the
> replication? Is it not possible to have a system where a write to one
> immediately triggers a write to all the others?
> Maybe if a server wants to write to a table it sends out a 'lock
> table' message to all the others, then does its write and sends the
> change to the others, and then unlocks the table after everybody have
> written the change.
>
> Like in a clustered web-server, how do I gurantee uptime if using
> replication? I can't go offline everytime there is a write to the db.
> Is the only solution to have the DB on a network FS?
>
> Thanks, cheers,
> Tobias
>

Why do you think the master must go offline to send changes to the slaves?
I've set up replication where all updates go to the master and then are
automatically sent to the slaves. Am I misunderstanding your question? If it
worked the way you envision it (master must go offline) what would the point
of replication be?

Evan

On Jul 26, 4:14 pm, "Evan Keel" <evank...@sbcglobal.net> wrote:

>
> Why do you think the master must go offline to send changes to the slaves?
> I've set up replication where all updates go to the master and then are
> automatically sent to the slaves. Am I misunderstanding your question? If it
> worked the way you envision it (master must go offline) what would the point
> of replication be?
>
> Evan

Hi,

Thanks! You didn't misunderstand, I guess I did :-)
I think this is what happens when you skim documentations and faqs and
consider too many designs till 2 in the morning and then wake up and
fire off a question. You're right there wouldn't be much point if it
didn't work that way. haha.

Cheers,
Tobias