Re: two instance -- one database
Date: Wed, 24 Sep 2008 18:34:14 -0700
Message-ID: <2ead3a60809241834g297974edh7ddb39dff2c41f98@mail.gmail.com>
Tom,
Imho, generally, pushing filter predicates over dblink does occur in newer versions (>8i) as long as you don't have local tables involved (as in this case).
John
On 9/24/08, Mercadante, Thomas F (LABOR)
<Thomas.Mercadante_at_labor.state.ny.us> wrote:
> Mark,
>
>
>
> Have you tested a multi-table join across the database link?
>
> Pick two very large tables.
>
> Create a query and run it on the source database with timing turned on.
>
> Run the same query on the remote database and compare the timings.
>
>
>
> This used to be a very big issue. The "where" clause used to be
> executed locally which means that all data from both tables was brought
> across the database link and joined locally. A very bad arrangement.
>
>
>
> I agree with Tim Gorman. It accomplishes nothing and adds complexity at
> your personal cost. You will be tuning this arrangement forever.
>
>
> Tom
>
>
>
> ________________________________
>
> From: oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Brady, Mark
> Sent: Wednesday, September 24, 2008 11:07 AM
> To: oracle-l
> Subject: two instance -- one database
>
>
>
> I have a friend (no really, this isn't some lame way of telling you
> about me but trying to hide that by ... )
>
>
>
>
>
> I have a friend, and at his company they have an Oracle database with
> tables and data. We'll call it Database A and they have another Database
> B that has views across dblinks to each of the tables in Database A. The
> data team says that this protects Database A from bad queries.
>
>
>
> So can anyone think of any possible benefit from this arrangement? Will
> administration be easier, queries faster, performance more predictable?
> Anything?
>
>
>
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-- Sent from Gmail for mobile | mobile.google.com John Kanagaraj <>< http://www.linkedin.com/in/johnkanagaraj http://jkanagaraj.wordpress.com (Sorry - not an Oracle blog!) ** The opinions and facts contained in this message are entirely mine and do not reflect those of my employer or customers ** -- http://www.freelists.org/webpage/oracle-lReceived on Wed Sep 24 2008 - 20:34:14 CDT