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RAC performance [message #177211] Tue, 13 June 2006 07:49 Go to next message
jlarchev
Messages: 3
Registered: June 2006
Location: Grenoble
Junior Member
Hello
I have a 2 node cluster with 10gR2 on Linux RH AS 4
Everyday I have to refresh a schema with the production data exported using expdp
The 1st thing I do is to drop the schema to recreate an empty one.
This "drop user xxx cascade" takes 45 minutes.
Then the import (impdp) takes about 9 hours.
The last night before refreshing the database I stopped the instance running in the 2nd node.
The same "drop user xxx cascade" only took 7 minutes. And the impdp took 6 hours.

Can anybody explain that ?

Re: RAC performance [message #177224 is a reply to message #177211] Tue, 13 June 2006 09:08 Go to previous messageGo to next message
Frank Naude
Messages: 4570
Registered: April 1998
Senior Member
Well, as you've just discovered - RAC is slower than a standalone instance. I've seen white papers claiming that certain operations can be up to 40% slower.

The more nodes you add to the cluster, the more overhead you add as Oracle needs to coordinate activities between all instances across the interconnect.
Re: RAC performance [message #177227 is a reply to message #177224] Tue, 13 June 2006 09:23 Go to previous messageGo to next message
jlarchev
Messages: 3
Registered: June 2006
Location: Grenoble
Junior Member
Hi,
Thanks for your response.
>>Oracle needs to coordinate activities between all instances across the interconnect ??
What does this exactly means ?
Re: RAC performance [message #179966 is a reply to message #177227] Thu, 29 June 2006 08:03 Go to previous message
Frank Naude
Messages: 4570
Registered: April 1998
Senior Member
Instances in the cluster need to talk to each other to keep things synchronized and prevent data corruption. Think data block transfers, lock mastering, etc.
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