Re: Database features vs software replication

[Charles Wilt <charles.wilt@xxxxxxxxx>]

It would seem like you could disable RI on the backup machine...it doesn't
really add any value assuming that RI is on on the primary machine.

Assuming it's strictly for backup...

If you had to do a role swap, you'd then need an additional step of
enabling RI before the users started using it.

Charles

On Thu, May 4, 2017 at 2:16 PM, Denis Robitaille <
denis_robitaille@xxxxxxxxxxxx> wrote:

> Hello,
>
> In our case, we had to make sure that the changes were applied on the
> target machine in the same order as on the production machine.
>
> The software we use (Vision) has the option of specifying multiple "apply
> queue" to speed up the replication. We had to restrict ourselves to one
> apply queue per replication "group" to avoid the possibility of a detailed
> record being updated before the corresponding header which would create an
> integrity violation.
>
> With our setup, we never get error related to constraint.
>
> Hope this help
>
>
> Denis Robitaille
> Chef de service TI - Solution d'entreprise
> Infrastructure et opérations
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> -----Message d'origine-----
> De : MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] De la part de
> Rob Berendt
> Envoyé : 4 mai 2017 15:41
> À : midrange-l@xxxxxxxxxxxx
> Objet : Database features vs software replication
>
> Due to our legacy software we're not doing a whole lot of referential
> integrity within the database itself.  For example, do not allow an order
> line created without a corresponding order header.  Therefore we're not
> using much (if any) foreign key constraints such as:
>
> create table ordhead (
> Ordernumber int as identity,
> customernumber int,
> primary key(ordernumber)
> );
>
> create or replace table ordline (
> ordernumber int not null,
> orderline int not null,
> itemNumber int,
> ordqty dec (15,5),
> constraint ordline_ordheadFK foreign key (ordernumber) references ordhead
> (ordernumber), constraint ordlinePK primary key (ordernumber, orderline) );
>
> I've heard from someone that this can be problematic at times with
> software based replication.  I am trying to get clarification but I think
> it had something to do with getting the order of the parent/child updates
> reversed.  This was causing an exclusive lock on the target causing them to
> stop/restart their software based replication to clear the lock.
> Sometimes as often as every other day.
>
> Have others experienced such issues?
>
> Rob Berendt
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