RE: database links and performance
- From: "Knight, Jon" <jknight@xxxxxxxxxxxxxx>
- To: "'thomas.mercadante@xxxxxxxxxxxxxxxxx'" <thomas.mercadante@xxxxxxxxxxxxxxxxx>, "'jdunn@xxxxxxxxx'" <jdunn@xxxxxxxxx>, Oracle-L@xxxxxxxxxxxxx
- Date: Tue, 8 Feb 2005 09:42:45 -0600
I can second Tom's comment that "bad things happen" when joining across
links. Especially if the remote tables have much size. Other strategies
are create a function on the remote DB to return just a small result set
across the link (if applicable.) Replicate certain data to your local DB
depending on needs/space.
We have also observed a performance hit (significant in some cases) even
when both DBs are on the the same box. That said, links are a great thing.
We use them all the time.
Jon Knight
Senior Database Analyst
2525 Horizon Lake Drive, Suite 120
Memphis, TN 38133
JKnight@xxxxxxxxxxxxxx
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Mercadante, Thomas F
Sent: Tuesday, February 08, 2005 8:49 AM
To: 'jdunn@xxxxxxxxx'; Oracle-L@xxxxxxxxxxxxx
Subject: RE: database links and performance
John,
I use them in a couple of applications and generally, they work fine. A
slow network is a slow network. Yes, it can hurt performance. If you think
that your network cannot support your application, then find another way to
do it.
A couple of tricks to consider:
If you need to join tables in the remote computer, consider creating a view
in that computer and calling that view from your local machine. It will
perform much better - basically, limit the joins from remote tables - bad
things happen.
Good Luck.
Tom
-----Original Message-----
From: John Dunn [mailto:jdunn@xxxxxxxxx]
Sent: Tuesday, February 08, 2005 9:40 AM
To: Oracle-L@xxxxxxxxxxxxx
Subject: database links and performance
We are considering using database links in Oracle 9i but are concerned about
performance.
Presumably the network can be a bottleneck when using database links.
Does anyone have any useful experiences with performance of database links?
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