SQL Anywhere database replication

Author

Design question

Edgard L. Riba

2005-08-31, 11:23 am

Hi,

I have the following need: I need to have the same database at 4
locations (ASA9), and have changes made in one location replicate to all
other locations.

All locations are connected on a TCP/IP network, and I can have servers see
each other without much problem. The only thing is that the network is
only some 95% reliable, so there are bound to be a couple of hours each
month where servers will be disconnected from each other.

I have tried to access a single database with my application, and it works,
but users want to have the server locally to minimize downtime and to
improve performance.

I guess this is what amounts to a "distributed" database.

The question is:
Can ASA properly handle this scenario? What is the correct way of doing
this?

BTW. I'm using SQLRemote now, but I'm not sure whether SQLRemote was
designed for this type of scenarios...

Thanks,
Edgard

Breck Carter [TeamSybase]

2005-08-31, 8:23 pm

Both MobiLink and SQL Remote were designed for exactly that
requirement (actually, they were designed for more *complex*
requirements, but work perfectly well on the simpler case).

SQL Remote might be easier to set up, MobiLink more likely to handle
the more complex requirements you've left out... not on *purpose* of
course :)

Breck

On 31 Aug 2005 09:24:22 -0700, "Edgard L. Riba" <elriba at rimith dot
com> wrote:

>Hi,
>
>I have the following need: I need to have the same database at 4
>locations (ASA9), and have changes made in one location replicate to all
>other locations.
>
>All locations are connected on a TCP/IP network, and I can have servers see
>each other without much problem. The only thing is that the network is
>only some 95% reliable, so there are bound to be a couple of hours each
>month where servers will be disconnected from each other.
>
>I have tried to access a single database with my application, and it works,
>but users want to have the server locally to minimize downtime and to
>improve performance.
>
>I guess this is what amounts to a "distributed" database.
>
>The question is:
>Can ASA properly handle this scenario? What is the correct way of doing
>this?
>
>
>BTW. I'm using SQLRemote now, but I'm not sure whether SQLRemote was
>designed for this type of scenarios...
>
>Thanks,
>Edgard
>

--
SQL Anywhere Studio 9 Developer's Guide
Buy the book: http://www.amazon.com/exec/obidos/A...7/risingroad-20
bcarter@risingroad.com
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www.risingroad.com

Andre Schild

2005-09-02, 11:23 am

Edgard L. Riba schrieb:
> Hi,
>
> I have the following need: I need to have the same database at 4
> locations (ASA9), and have changes made in one location replicate to all
> other locations.
>
> All locations are connected on a TCP/IP network, and I can have servers see
> each other without much problem. The only thing is that the network is
> only some 95% reliable, so there are bound to be a couple of hours each
> month where servers will be disconnected from each other.
>
> I have tried to access a single database with my application, and it works,
> but users want to have the server locally to minimize downtime and to
> improve performance.
>
> I guess this is what amounts to a "distributed" database.
>
> The question is:
> Can ASA properly handle this scenario? What is the correct way of doing
> this?
Yes, it can.

But of course you must make sure that your primary keys remain unique.
And (depending on the business you do) how to resolve update conflicts.

André

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