RE: speeding up expdp
Date: Sat, 5 May 2012 17:41:56 -0700
I feel sorry for you, but misery loves company :=)
4GB database full backup using RMAN takes over 6 hours to NFS.
Off the tangent now.
dumpfile=migration_wh%U.dmp <== important since this was the mistake I made before. PARALLEL=12 Hopefully, it's that easy. Otherwise, there are several articles on configuring NFS for use with Oracle.
Disparity Breaks Automation (DBA)
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From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Maureen English Sent: Saturday, May 05, 2012 10:53 AM
To: D'Hooge Freek
Subject: Re: speeding up expdp
The database is Enterprise Edition.
I've tried the export with parallel=2, parallel=4 and parallel=6 and
all take about the
same amount of time. I also set the database parameters parallel_min_servers and
parallel_max_servers to 6 and 12, respectively. I see the processes start up in the
database at the beginning of the export, but I didn't check to see how many were
still running when the export was done with everything but these last 2 tables. I've
just been watching the dump files...only 2 are being written to at the end.
I do believe that both of these tables have a lob column. Does that
mean I just have
to live with the 7.5 hours? At least the import to the new machine only takes about
I'm also excluding indexes/constraints for the export and import.
I'm pretty sure I read through the checklist document, but not the
other 2. I'll
check them out.
On Fri, May 4, 2012 at 9:51 PM, D'Hooge Freek <Freek.DHooge_at_uptime.be> wrote:
> Is your database an enterprise edition or a standard edition?
> If you have an enterprise edition, then expdp can work with multiple parallel slaves.
> One thing you then need to look for is if the 2 large tables are also exported in parallel or if only 1 process is exporting them.
> If the table for instance has a lob column, then oracle can't export it in parallel.
> Sometimes Oracle chooses for some reason wrongfully the direct path method for a table, which disables the parallel feature. In that case you can try to force expdp to use the external table method.
> The notes below give you a good starting point on how to improve the performance of datapump and how to check what is happening:
> Checklist for Slow Performance of Export Data Pump (expdp) and Import DataPump (impdp) [ID 453895.1]
> Export/Import DataPump Parameter TRACE - How to Diagnose Oracle Data Pump [ID 286496.1]
> Export/Import DataPump Parameter ACCESS_METHOD - How to Enforce a Method of Loading and Unloading Data ? [ID 552424.1]
> Kind regards,
> Freek D'Hooge
> Oracle Database Administrator
> email: freek.dhooge_at_uptime.be
> tel +32(0)3 451 23 82
> disclaimer: www.uptime.be/disclaimer
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Maureen English
> Sent: zaterdag 5 mei 2012 3:58
> To: oracle-l_at_freelists.org
> Subject: speeding up expdp
> We have an Oracle 10g database on RHEL5. I would love to find a way
> to speed up the export
> of the database. It currently takes about 7.5 hours. The main
> problem is with 2 tables, one of
> which is 30GB, the other is 70GB.
> I've looked through the documentation for expdp, as well as gone
> through all of the Metalink notes
> I could find that were related to expdp running slowly. I've tweaked
> things here and there, but I
> can't get the export to run any faster. I know the system is a little
> slow, and I'm writing to an
> NFS mounted drive, but I was really hoping that this could be done
> faster. I haven't tried using
> exp instead, but I'm considering that for another test.
> Any suggestions?
> - Maureen