I don't know the direct answer, but I found the same solution.
I had a query that did a join of two tables in a local database
and then inserted into a remote db table. Sort of...
insert into table_at_remote
select a.col1, b.col1
from tab1 a, tab2=20
where a.col2 =3D b.col3
...and it took for-blinking-ever. I created a global temporary
table, inserted into that, and then inserted from the GTEM
table to the remote table and processing dropped to mere moments.
It was a puzzlement to me because the work (ie: the join) I=20
presumed was being done on the local machine prior to the=20
insert to the remote table. My fix was a late-night-oh-my-
doG-fix-the-problem solution and I never got the time to go
back and find the why.
Cheers,
Mike
-----Original Message-----
From: Kevin Lange
Sent: Wednesday, September 22, 2004 2:44 PM
To: Oracle-L (E-mail)
Subject: DB Links
Does anyone happen to have a reasonable explaination on what happens to =
a
query when you try to access tables accross db_links ?? Does it still =
use
the indexes on the remote machine ?? Does it bring all the data locally
into temp tables ??
Any info will do. Book names .... Actual explainations ... directions =
to
web sites ... Anything.
We have a procedure, a fairly complex procedure, that takes about 13 =
hours
to run when it is ran against tables that exist accross a DB link. But,
when we copy all the tables locally, it runs in about an hour. We would
like to try and find a way to fix this. But first, I need to know =
exactly
what is happening when the cursor access those linked tables.
Any help would be appreciated.
Kevin
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