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Export utility taking more time [message #420283] Fri, 28 August 2009 02:39 Go to next message
anwar786
Messages: 25
Registered: May 2009
Location: bangalore
Junior Member
HI guys

We are running export full backup of a database which is 11.47gb
under dba_segments.

script is
exp file=loc1.dmp log=loc1.log full=y buffer=1610612736 statistics=none

the problem is
1.it takes 17hours to complete. even though we gave buffer of 1.5gb
we are also taking rman full backup which only takes less than an hour.

2.other thing is that after completing it acoounts to only 1.1gb of dump file which we were surprised because such a small file is taking more than 16hrs to fully export. so we checked in a test server to verify that all is there by importing dump and all schemas were there.

we queried initial extents of all tables which we found are larger from 128k to 2mb with uniform extents.

also 70% of tables in this database are empty. which belonged to various schemas.

can anyone help us out y this export is taking so long(17hrs)

this isssue we are facing in one of our clients place.

relpy soon.




Re: Export utility taking more time [message #420327 is a reply to message #420283] Fri, 28 August 2009 05:54 Go to previous messageGo to next message
Mahesh Rajendran
Messages: 10671
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
Is there any rationale for using buffer=1610612736 ?

>>2.other thing is that after completing it acoounts to only 1.1gb of dump file
That is normal. Exported dumps will have only the index DDL and not real "index Segments". During import indexes are rebuilt on target database.
Though it has nothing to do with performance of export, i would add compress=n during export process.

>>can anyone help us out y this export is taking so long(17hrs)
Your hardware.
Your Filesytem.
Export is just a serial process.
Generic hints are given here
http://www.orafaq.com/wiki/Import_Export_FAQ#How_can_one_improve_Import.2F_Export_performance.3F

Check the docs and see how to use BUFFER and RECORDLENGTH

http://download.oracle.com/docs/cd/B19306_01/server.102/b14215/exp_imp.htm

[Updated on: Fri, 28 August 2009 05:54]

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Re: Export utility taking more time [message #420627 is a reply to message #420283] Tue, 01 September 2009 01:10 Go to previous messageGo to next message
anwar786
Messages: 25
Registered: May 2009
Location: bangalore
Junior Member
Thanks FOr replying

I'll check and tell.
Re: Export utility taking more time [message #420707 is a reply to message #420627] Tue, 01 September 2009 13:07 Go to previous messageGo to next message
sujeetsaxena16
Messages: 9
Registered: May 2007
Location: mumbai
Junior Member

Hi,

If u are getting delayed in export dump Check three Levels while running the export.

1.Check the memory level of server
2.How many users Login that this while you are using the export backup
3.Use the Direct=y and compress=n ,index=n parameter Defenatlly it will help out u.

Regards
Sujeet Saxena
Re: Export utility taking more time [message #420710 is a reply to message #420283] Tue, 01 September 2009 13:51 Go to previous messageGo to next message
joy_division
Messages: 4617
Registered: February 2005
Location: East Coast USA
Senior Member
anwar786 wrote on Fri, 28 August 2009 03:39

also 70% of tables in this database are empty. which belonged to various schemas.



But the high water mark has probably not been reset. If you had a table with millions of rows and now it has none because they were all deleted, this table will still take a long time to export.
Re: Export utility taking more time [message #427482 is a reply to message #420327] Thu, 22 October 2009 16:44 Go to previous message
psoftneto
Messages: 44
Registered: July 2008
Member
Hi,

Can some one confirm that we are not obliged to use the same value for recordlength for export and import?
Since documentation says it's the size of the Export I/O buffer, why should this parameter be useful when export and import are on different systems?
Also I am a little bite confused between recordlength and buffer.
Is recordlength the buffer for I/O dump file and buffer for database inserts?
Thanks.
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