Hi!

What is your goal? To finish data transfer in the shortest time or keep
hardware utilization maximum during transfer?
I think you should concentrate on keeping the time for doing data transfer
low.

Depending on your network - in case of gigabit (or 10 Gb) you could look at
enabling jumbo frames, which enable ethernet packets up to 9000 bytes. Also
set (SDU=32768) in your listener and tnsnames.oras (you can set it with
normal 1500 byte frames as well).

About parallellism, you might want to run several bulk inserts over dblink
to fully utilize your network (fill the "gaps" when one session is busy
inserting, thus not using the network). But if your source disk array (or
CPUs) are slow then they might be the bottleneck.
If you got SAN and a temporary spare server, do a BCV copy or mirror split,
open up several clones of a database and copy data from all of them.

Also, when you have SAN, there's no need for network transfer at all - you
just mount the filesystem with dump/exportfiles on target database and do
the load from there. If your operating systems are different, then just dump
to raw device, with pipe and tar for example, or completely raw, remembering
your data sizes. Note that in some (older) operating systems there were few
blocks in beginning of device which were used (and written) by operating
system (Tru64 had the largest I know - 64k). Thus you had to make sure you
didn't write anything there (oseek=65536 for dd for example).

If downtime isn't an issue for you, it might not be worth trying above
recommendations, but in RVLDBs (really very large databases) all of this can
help a lot.

Tanel.
----- Original Message ----- 
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
Sent: Tuesday, August 26, 2003 5:54 PM


> Taniel, Binley
>    Thanks for the excellent suggestions.
>    At this point we have been testing with two smaller test systems,
moving
> a single table at a time, but initial indications are that the performance
> order is:
> 1. Perl dump to CSV / ftp / SQL*Loader
> 2. Copy across database link
> 3. Export/ ftp / import
>
> I need to re-run the tests once the target production system is available
to
> re-confirm which is faster. I am pretty confident in the ability to run
> multiple SQL*Loader and import sessions simultaneously. I am a little
> nervous about the ability of the database link to scale to enough
> simultaneous sessions to keep the RAID sets maxed out on the target
system.
> Several years ago when I was doing a large conversion I hit that limit.
Some
> days I wonder if we are the beneficiary or victim of our prior experience.
> Oh well thanks for all the good suggestions, on to testing, testing,
> testing.
>
> Dennis Williams
> DBA, 80%OCP, 100% DBA
> Lifetouch, Inc.
> [EMAIL PROTECTED]
>
>
> -----Original Message-----
> Sent: Monday, August 25, 2003 7:09 PM
> To: Multiple recipients of list ORACLE-L
>
>
> Hi!
>
> What about several insert /*+ APPEND NOLOGGING */ commands over database
> link run in parallel? (Possibly over dedicated network). This is fast and
is
> easier (in case you don't hit any compatibility problems). If you happen
to
> be running on Windows for some reason, you could try to use named pipes
> network protocol instead of TCP as well.
>
> Tanel.
>
> ----- Original Message ----- 
> To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
> Sent: Monday, August 25, 2003 11:04 PM
>
>
> > Thanks Tanel
> >   We will undoubtedly use export/import for the many small tables. We
are
> > looking for alternatives that will perform even faster. The insert phase
> > seems to be the slowest part, and that is where SQL*Loader in direct
path
> > really shines. Now the next issue is how to produce a CSV file as fast
as
> > possible, and so far it looks like Jared's Perl program is the clear
> winner.
> >
> > Dennis Williams
> > DBA, 80%OCP, 100% DBA
> > Lifetouch, Inc.
> > [EMAIL PROTECTED]
> >
> >
> > -----Original Message-----
> > Sent: Monday, August 25, 2003 1:05 PM
> > To: Multiple recipients of list ORACLE-L
> >
> >
> > Hi!
> >
> > Spooling from sqlplus is VERY slow.
> > Is the source database Oracle? Then use export/import
> > If not, is there an ODBC driver for source database? Then use Oracle
> > heterogenous services and do your transfer directly, without any
> > intermediate files.
> > Or use some very expensive software for doing this simple job...
> >
> > Tanel.
> > P.S. if you definitely want to spool to textfile fast, Sparky could be
> what
> > you want...
> >
> > ----- Original Message ----- 
> > To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
> > Sent: Monday, August 25, 2003 7:24 PM
> >
> >
> > > Jared - Thanks for posting this. At the moment, we are preparing to
move
> > > large database to a new server. Based on the advice you posted several
> > > months ago, we have been testing SQL*Loader and as you predicted, it
is
>
> > > indeed fast. But also as you predicted, using SQL*Plus to create a CSV
> > isn't
> > > very fast. Am I correct in assuming the dump.sql will not be the best
> > choice
> > > for large tables? We are installing perl since you mentioned that
would
> > > probably be much faster.
> > >
> > > Dennis Williams
> > > DBA, 80%OCP, 100% DBA
> > > Lifetouch, Inc.
> > > [EMAIL PROTECTED]
> > >
> > >
> > > -----Original Message-----
> > > Sent: Monday, August 25, 2003 9:40 AM
> > > To: Multiple recipients of list ORACLE-L
> > >
> > >
> > > http://www.cybcon.com/~jkstill/util/dump/dump.html
> > >
> > > On Mon, 2003-08-25 at 05:39, Imran Ashraf wrote:
> > > > Hi,
> > > >
> > > > Whats the best way to write the results of a SQL query to a CSV
file?
> > > >
> > > > Thanks.
> > > >
> > > > _________________________________________________________________
> > > > Hotmail messages direct to your mobile phone
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> > > > -- 
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> -- 
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> -- 
> Author: Tanel Poder
>   INET: [EMAIL PROTECTED]
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