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Home > Archive > Oracle Databases > August 2005 > purpose of db-links
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purpose of db-links
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| Hi!
I have seen db-links used in views, triggers etc.
This results in very bad performance.
Is there an good reference to read about, when and when not to use db-links?
Greetings
Bjørn
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| Mark Malakanov 2005-08-01, 9:25 am |
| Depends why do you use them. You usually use them when you have to
get/put data from/into another DB.
You can avoid to use DB links directly from triggers and other code by
separating of local DML code and a propagation of data modifications -
Replication. There are two major facilities that can help with that.
Standard Replication and Adwanced Replication. Although they will use DB
Links too (inside), your app will work with a local replica of remote
data, that is much faster. Replication will move data or data changes
here and there. It is called asynchronous replication.
However the asynchronous replication from remote to local will cause
some de-synchronization in data between them. The latency of data
modifications coming. That is the price. The latency depends on what
type of replication you use and settings.
It is achievable to have asynchronous replication based on Streams (10g)
that can be close to real time.
If totally momentarily data is required to be accessed, you can not
avoid using db links.
bdj wrote:
> Hi!
> I have seen db-links used in views, triggers etc.
> This results in very bad performance.
> Is there an good reference to read about, when and when not to use db-links?
> Greetings
> Bjørn
>
>
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| Thank you!!
"Mark Malakanov" <markmal@rogers.com> skrev i en meddelelse
news:JMCdnR5XmvywqHP
fRVn-sA@rogers.com...[color=darkred]
> Depends why do you use them. You usually use them when you have to get/put
> data from/into another DB.
> You can avoid to use DB links directly from triggers and other code by
> separating of local DML code and a propagation of data modifications -
> Replication. There are two major facilities that can help with that.
> Standard Replication and Adwanced Replication. Although they will use DB
> Links too (inside), your app will work with a local replica of remote
> data, that is much faster. Replication will move data or data changes here
> and there. It is called asynchronous replication.
> However the asynchronous replication from remote to local will cause some
> de-synchronization in data between them. The latency of data modifications
> coming. That is the price. The latency depends on what type of replication
> you use and settings.
> It is achievable to have asynchronous replication based on Streams (10g)
> that can be close to real time.
> If totally momentarily data is required to be accessed, you can not avoid
> using db links.
>
>
>
> bdj wrote:
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