Yes, be particularly careful when accessing tables across database links.
The threshold for when a FTS is more efficient than an index access changes.
Also, i found out this week, that if you use in-line views in your query,
Oracle can send the whole in-line view across the database link!. In the
following example, oracle will execute the inline view on the cust database!
Without the inline view, oracle chose a FTS of tablea hash joined to FTS of
tableb.
SELECT *
FROM (SELECT *
FROM tablea@cust, tableb@cust
WHERE tablea.key = tableb.key) t
,tablec
WHERE tablec.key = t.key
-----Original Message-----
Sent: Friday, November 08, 2002 2:43 PM
To: Multiple recipients of list ORACLE-L
Paula
I was hoping someone with more specific experience in this area. Here is
a quote from Oracle Performance Tuning 101:
Be particularly when joining a local table to a remote table.
My vote if you only have 60 rows would be to populate a local table with
those rows before running your query.
Dennis Williams
DBA, 40%OCP
Lifetouch, Inc.
[EMAIL PROTECTED]
-----Original Message-----
Sent: Friday, November 08, 2002 11:40 AM
To: Multiple recipients of list ORACLE-L
BTW,
Was doing join of views pointing to tables through 2 database links and
gateway. Just wondering - faster to move the tables then perform join
locally esp. if I can do CTAS each time - hmmmm.
-----Original Message-----
Sent: Friday, November 08, 2002 12:34 PM
To: '[EMAIL PROTECTED]'
Trying to bring over 60 rows with database link and write to table using
CTAS. It is taking forever - going through Oracle - going through another
Oracle that is hooked up with a gateway to Informix - yuck!!
The waits are:
Event Waits Waits/sec % total Wait Time (ms) Wait Time/sec %
total Average Wait SQL*Net more data from dblink 1352
80.8709175738725 99.1202346041056 14250 852.374685967221
0 0
Any ideas how to speed up other than getting another gateway, creating ascii
file and using direct load. Is there a way to tune related to Net8,
database links?
Thanks,
Paula
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