Post date: 02-Jul-2009 09:57:03
I am cloning regularly Production RAC environment to the Development or Quality acording to the customer needs. For this we use RMAN duplicate to clone the RAC cluster database to whole new environment. This cloning occurs every month end.
We faced many times the problem of slow performance of RMAN during the duplication. Specifically during the last steps RMAN takes too long time to catalog datafile copies. And this time can be to the tune of 10mins or even 15mins per datafile. In that case, it is not possible to respect the SLA for the maintenance activity.
I found one ineteresting Oracle BUG and the workaround relted to it. Please check the following.
Doc ID: 462879.1 and refer to Bug 6167501 - CATALOG DATAFILES DURING DUPLICATE TAKES A LONG TIME mentioned in the References section.
It says to set up optimizer_mode parameter on session level which will run the duplicate to value " rule ", something like following
run{
sql 'alter session set optimizer_mode=rule';
....
....
duplicate target database to dest;
}