Re: Database links...again

Cheers for the reply Jonathan......our server ( NT4 !! ) has been crashing around our ears for the past few days so it was decided to rebuild it from scratch, put a clean installation of Oracle on and then recreate all of the databases using backed up datafiles...hey presto.....database links run without a hitch....it looks like the whole bloody thing was due to NT problems....

If anything goes wrong again I'll be back

Cheers

Steve Bright

steve.bright_at_capgemini.co.uk

Jonathan Lewis wrote in message
<931448568.8784.0.nnrp-06.9e984b29_at_news.demon.co.uk>...
>I don't think setting SDU will make any difference
>because you are implicitly using single row fetches
>in the loops, so the volume of data being passed
>is much less than the default SDU anyway.
>
>Are both instances configured identically ?
>Have you traced the SQL that hits the remote
>instance to see what it actually does, and if
>it is in some way different from the local SQL,
>or if its performance characteristics are
>different (does one database have 10 times as
>many objects at the other ?)
>
>The other thing to bear in mind is that a single
>instance test may operate fully in memory, but
>when the two instances have to be running
>concurrently they may be forcing each other to
>swap to disc all the time.
>
>Try the test with:
> a) Using a loopback connection as the 'remote'
> b) doing a test with local looping inside the remote
> c) remote looping inside a local
>to see if the results give you any further clues.
>
>
>BTW - SDU has to be set in both the tnsnames.ora
>and the listener.ora to be effective.
>
>--
>
>Jonathan Lewis
>Yet another Oracle-related web site: www.jlcomp.demon.co.uk
>
>Steve B wrote in message <7m2fv3$9d7$1_at_taliesin.netcom.net.uk>...
>>At present remote queries across a database link are taking at least ten
>>times as long to execute compared to being directly executed on the remote
>>instance...I've included a test procedure at the end of this post...
>>
>>Is there any reason why the procedure below shold be so slow ????
>>
>>What parameters can I set to improve this performance ??
>>
>>I've read about the Session Data Unit ( SDU ) parameter for tnsnames
>>configuration....
>
>
>
Received on Thu Jul 08 1999 - 17:56:33 CDT