RE: rules for database link usage
- From: "Uzzell, Stephan" <SUzzell@xxxxxxxxxx>
- To: "'curtisbl@xxxxxxxxx'" <curtisbl@xxxxxxxxx>, "backseatdba@xxxxxxxxx" <backseatdba@xxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 17 Feb 2014 16:05:11 +0000
Bobby,
Could you say a bit more about the view issue (or point me towards some
documentation)? One of the many fires we're fighting is a performance issue
where a DB link is involved... We have not yet directly implicated the DB Link
in the performance problem, but...
Thanks,
stephan
Stephan Uzzell
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Bobby Curtis
Sent: Monday, 17 February, 2014 10:56
To: backseatdba@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: rules for database link usage
Jeff,
This is a slippery slope. Database Links can be good; however, I've seen the
wrong use of them where they cause a problems. Example, if you query a view on
the remote side through a dblink, your wait times may go up because you have
wait for the view to compile and then return the result set. This extends your
connection and retrieval times.
If you have to use a database link, I would use materialized views on the
remote side to keep the data readily available. This way you are not compiling
on the fly and waiting for the result set to be returned.
Ideally, I try to keep the data as close as possible to where the execution is
going to happen.
Just my 2cents.
Bobby
From: oracle-l-bounce@xxxxxxxxxxxxx<mailto:oracle-l-bounce@xxxxxxxxxxxxx>
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jeff C
Sent: Monday, February 17, 2014 10:48 AM
To: oracle-l@xxxxxxxxxxxxx<mailto:oracle-l@xxxxxxxxxxxxx>
Subject: rules for database link usage
What are you rules for using database links in a production application? We
currently have an application that needs data from another database and I am
torn between having them just use a database link or copying the data to their
database using various methods.
I am leaning towards duplicating the data because I prefer to not have this
database dependent on the other or one causing havoc on the other. But I guess
if that didn't matter what in general are your rules?
Jeff
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