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Regarding views and synonyms [message #220850] Thu, 22 February 2007 06:42 Go to next message
Suresh B
Messages: 10
Registered: October 2003
Junior Member
One of our production database is being upgraded from its current 8i version to 9i. This results in impact on the db link, as db links between Upgraded database (Oracle version 9.2.0.Cool and destination database (Oracle version 7.3.4) are no longer supported by Oracle Corporation.

The above db link issue between Oracle 9i and Oracle 7 versions can be handled by using an intermediate 8i database in between the 7 and 9 versions. This results in 9i version interacting with 8i version and 8i with 7 version without any problems.

The solution can be attained by creating views on the intermediate database pointing to the 7.3.4 DB using the database links. Synonyms referring to these views on the intermediate database would be created on the 9.2.0.8 database with the same name as that on the intermediate database using db links.

Here would like to know that, is the view or synonym will give the better performance when we fetch/transfer the data thru intermediate database.

Your expert comments would really help me.

Regards,
Suresh.
Re: Regarding views and synonyms [message #220851 is a reply to message #220850] Thu, 22 February 2007 06:47 Go to previous messageGo to next message
Mahesh Rajendran
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Registered: March 2002
Location: oracleDocoVille
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>> is the view or synonym will give the better performance when we fetch/transfer
Not essentially.
Synonyms are known to hinder the performance.
Searh the forum for related posts.
IMHO, there are bigger fish to fry here.
As you might be aware 9i will be desupported very soon Smile.
Re: Regarding views and synonyms [message #220855 is a reply to message #220851] Thu, 22 February 2007 06:59 Go to previous messageGo to next message
Suresh B
Messages: 10
Registered: October 2003
Junior Member
Mahesh,
Can you pls put me into correct article which gives more info about synonyms and views or can you explore on this.

Thanks,
Suresh.
Re: Regarding views and synonyms [message #220861 is a reply to message #220855] Thu, 22 February 2007 07:19 Go to previous messageGo to next message
Mahesh Rajendran
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Just search. Many related posts.
One such.
http://www.orafaq.com/forum/m/215129/42800/?srch=synonyms#msg_215124
On other hand views may be behave almost the same
http://www.orafaq.com/forum/m/211254/42800/?srch=about+to+write#msg_211252
Going through all this pain just to migrate to 9i is not worth, as it will desupported real soo. Why not migrate to 10g?
The bigger issues i was ranting about is
you are using dblink across versions where there is a considereble differences in CBO behaviour. Performance issues with synonyms is just a part of it.
Re: Regarding views and synonyms [message #220869 is a reply to message #220850] Thu, 22 February 2007 08:08 Go to previous messageGo to next message
joy_division
Messages: 4640
Registered: February 2005
Location: East Coast USA
Senior Member
Suresh B wrote on Thu, 22 February 2007 07:42


The above db link issue between Oracle 9i and Oracle 7 versions can be handled by using an intermediate 8i database in between the 7 and 9 versions. This results in 9i version interacting with 8i version and 8i with 7 version without any problems.

The solution can be attained by creating views on the intermediate database pointing to the 7.3.4 DB using the database links. Synonyms referring to these views on the intermediate database would be created on the 9.2.0.8 database with the same name as that on the intermediate database using db links.



Wow, I'd just like to add that I thought I was the only person in the world who had to do something like this. At one time, we had 7.3, 8i, 9i and 10g all running different production databases and I had to use the 8i database to create a "bridge" between 10g and 7.3 and vice versa.
It might not apply to you, but Forms will not work using this method due to the way ROWID has changed through the versions.

Re: Regarding views and synonyms [message #220928 is a reply to message #220869] Thu, 22 February 2007 15:09 Go to previous message
Littlefoot
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Registered: June 2005
Location: Croatia, Europe
Senior Member
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I'm joining the club too. Used 8i as a bridge between 7.1 and 9i.
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