Re: create imp and exp Oracle as single-task binaries?

From: Tanel Poder <tanel.poder.003_at_mail.ee>
Date: Wed, 02 Jul 2003 07:51:57 -0700
Message-ID: <F001.005BDAF1.20030701154029@fatcity.com>

I once experimented with it (8.1.7.smth on linux), but started having crashes. Don't remember what exactly crashed, but it didn't work. I believe last version where it was supported, was 8.0?

Anyway, even if it would run correctly, I wouldn't use it anywhere else than during one-time migrations or maybe loading staging databases. Of course ST binaries behaviour should be thouroughly tested before.

Also, if your system is IO bound, you won't get any benefit from STL, because the same amount of data has to be read during exp anyway... I'd set direct parameter to true and recordlength maximum for increasing exp speed. Buffer parameter doesn't have any effect when doing direct mode export.

For imp, there's lot's of opportunities for speeding up it's speed. For huge tables/schemas I would:

1) Import the table definitions without any constraints or indexes.
2) Disable triggers if any.
3) Import data using large buffer parameter. (Import is always done in

conventional mode). For extremely huge tables CTAS over dblinks could be used instead.
4) Enable triggers
5) Get index commands using indexfile from structure export (use indexes=y constraints=y indexfile=xxx to get bot stand-alone index definitions and constraint-index defs)
5.1) Modify index creation commands to use parallel clauses and nologging 5.2) Run index creation commands
6) Run structure import again with indexes=n rows=n constraints=y to enable constraints

I hope I didn't miss anything... There's actually more stuff which you could use such are unsupported _disable_logging and _wait_for_sync parameters which you could use during migrations or test environments...

So, there's plenty of other stuff which to try out first before single task linking.

Cheers,
Tanel.

Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, July 02, 2003 12:49 AM

> Hi:
>
> I saw the following message while searching web for some tips to improve
exp
> speed. Has anyone tried this "un-supported" way and found improved
> performance? Had any problems? I don't have a machine that I can try this.
>
> Guang
>
> ---------
> Oracle Export/Import Scripts: How to create imp and exp Oracle as
> single-task binaries
> Posted by: Administrator
>
>
> If someone is interested in implementing the create a new Oracle import
> binary as a single-task, see the steps below.
>
> The import and export programs (imp/exp) run in two task mode to protect
the
> SGA from potential corruption by user programs. By relinking these two
> programs in single task mode you can gain much improvement in speed. In
many
> cases up to 30%.
>
> To read the complete article, click on the Read more ... link.
>
> Submitted by our member: Chris
>
>
> Oracle themselves use this method although it is NOT supported by Oracle.
>
> Running in single-task is much faster but it requires more memory since
the
> Oracle executable's text is no longer shared between the front-end and
> background processes. If you need to transfer large amounts of data
between
> databases, relink the executale for greater efficiency.
>
> To relink the RDBMS kernel and create the two new imp/exp programs, use
the
> following:
>
> $ cd $ORACLE_HOME/rdbms/lib
> $ make -f ins_rdbms.mk singletask
> $ make -f ins_rdbms.mk expst
> $ make -f ins_rdbms.mk impst
> $ make -f ins_rdbms.mk sqlldrst
> $ mv expst $ORACLE_HOME/bin/
> $ mv impst $ORACLE_HOME/bin/
> $ mv sqlldrst $ORACLE_HOME/bin/
>
> Now use expst and impst instead of imp or exp when doing export & import
of
> data.
>
> Let me know if you have any problems, or improve the above procedure
> somehow.
>
> Thanks.
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Guang Mei
> INET: [EMAIL PROTECTED]
>
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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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Received on Wed Jul 02 2003 - 09:51:57 CDT