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oracle exports

james gould
Frequent Advisor

oracle exports

Oracle exports taking much longer at different
times on server running 11.0. Some days the
process will run in 20 minutes when the export
is run other times it will take 3 hours to run.

Not much is happening on the system at all days. The export will sometimes run from 9%
to 25% when it runs longer.
6 REPLIES
A. Clay Stephenson
Acclaimed Contributor

Re: oracle exports

Hi James:

You really don't give us much to go on but I will take a few wild guesses (I will assume that all these exports are the same and not a full vs incremental).

1) Your fast exports may be done soon after most tables have been defragmented.
2) If you are running an AutoRAID, usage patterns have caused most of the tables to be stored in RAID 0/1 rather than RAID 5.
3) More is actually running on your server at times than you think.

You really need to use Glance and/or Measureware to gather performance stats during both the good and bad times and I suspect the problem will become obvious. You can install 30 day Trial version of Glance if you don't already have it.

If it ain't broke, I can fix that.
Andreas D. Skjervold
Honored Contributor

Re: oracle exports

Hi
Just a tip on how to get the export time reduced:
Use direct path export (DIRECT=Y).
This will speed up your export and your subsequent import of this dump file even more. This due to the fact that Oracle loads data directly into place in the tables (not as sql inserts).
2 things to be aware of is that you can't export LOB or BLOB data, and during import data is placed over the High Watermark in the segment (table). This might require more space in your segments.

Andreas
Only by ignoring what everyone think is important, can you be aware of what everyone ignores!
Volker Borowski
Honored Contributor

Re: oracle exports

If you say "not much" happens, where does it come from ? Is the application accessing the database running during the export ?
If this is the case, you might have a LOCK problem.
If the application LOCKs a table in exclusive mode, the export will wait until the LOCK is released.
If the user who locks this table is in a meeting, it might take some time.....

Stop the application during the export.

Hope this helps
Volker
Alexander M. Ermes
Honored Contributor

Re: oracle exports

Hi there.
Some basics :
place the database in dba mode for export / import, so that no user has any influence.

Set the NLS language to American_America.

The direct export / import does not touch the logfiles, that is the reason for the speedup with direct=y.

Did you spread the database file over several disks and controler interfaces ?

Rgds
Alexander M. Ermes
.. and all these memories are going to vanish like tears in the rain! final words from Rutger Hauer in "Blade Runner"

Re: oracle exports

the exports time depends on the total no of objects and the total no of rows.suppose during the time of 20 min there must less no of records in the database.pls verify the same.

jp
Carlos Fernandez Riera
Honored Contributor