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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Query results to .csv/use of dblinks
Thanks for your input. Discussion here is to keep maximum use of dblinks for
data load/transfer from one server to another.
Regards
Rafiq
Reply-To: ORACLE-L_at_fatcity.com
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
Date: Tue, 26 Aug 2003 12:49:27 -0800
You can also close the dblink to avoid having many open idle sessions on the
remote database.
alter session close database link dblink;
Stephane Paquette
Administrateur de bases de donnees
Database Administrator
Standard Life
www.standardlife.ca
Tel. (514) 499-7999 7470 and (514) 925-7187
stephane.paquette_at_standardlife.ca <mailto:stephane.paquette_at_standardlife.ca>
-----Original Message-----
Rafiq
Sent: Tuesday, August 26, 2003 3:54 PM
To: Multiple recipients of list ORACLE-L
Tanel,
A quick question? How many open dblinks you have used at one time without any issues? Default setting in init.ora is 4(if I am not wrong) and I never used it more than that. If Dennis wants to use more than 4 dblinks at one time, he should modify this param(open_dblinks) in init.ora, right.
Regards
Rafiq
Reply-To: ORACLE-L_at_fatcity.com
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
Date: Tue, 26 Aug 2003 09:14:26 -0800
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" <ORACLE-L_at_fatcity.com>
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.
> dwilliams_at_lifetouch.com
>
>
> -----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" <ORACLE-L_at_fatcity.com>
> 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.
> > dwilliams_at_lifetouch.com
> >
> >
> > -----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" <ORACLE-L_at_fatcity.com>
> > 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.
> > > dwilliams_at_lifetouch.com
> > >
> > >
> > > -----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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> > > >
> > > > --
> > > > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > > > --
> > > > Author: Imran Ashraf
> > > > INET: imran9a_at_hotmail.com
> > > >
> > > > Fat City Network Services -- 858-538-5051
http://www.fatcity.com
> > > > San Diego, California -- Mailing list and web hosting
services
> > >
> ---------------------------------------------------------------------
> > > > To REMOVE yourself from this mailing list, send an E-Mail message
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> > >
> > >
> > > --
> > > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > > --
> > > Author: Jared Still
> > > INET: jkstill_at_cybcon.com
> > >
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> > > San Diego, California -- Mailing list and web hosting
services
> > >
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Tanel Poder INET: tanel.poder.003_at_mail.ee Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). _________________________________________________________________ MSN 8: Get 6 months for $9.95/month. http://join.msn.com/?page=dept/dialup -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: M Rafiq INET: rafiq9857_at_hotmail.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Stephane Paquette INET: stephane.paquette_at_standardlife.ca Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). _________________________________________________________________ Get MSN 8 and enjoy automatic e-mail virus protection. http://join.msn.com/?page=features/virus -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: M Rafiq INET: rafiq9857_at_hotmail.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Tue Aug 26 2003 - 16:09:27 CDT
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