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Connor McDonald

Thanks for the question.

Asked: February 04, 2017 - 6:33 pm UTC

Last updated: February 05, 2017 - 5:52 pm UTC

Version: oracle 10g

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HI

we need to migrate DB from 8 core system to 4 core system. one of my DB engineer is saying On the startup Oracle reads the processor and “stamp” on the database. After that, next time when you start the database Oracle only override the stamp if the number of processor is greater than before. If the processor is less than before Oracle DO NOT override the stamp.
we don't have any special CPU_COUNT seetings in SPfile

is this true statement?

and Connor said...

I dont know what you mean by "stamp", but if my interpretation of the sentiment is correct, then that is not a correct statement.

When you start your system on a 4 core system (and cpu_count has not been specified in init.ora), it will show a cpu_count value for *that* server, not any previous server.

In fact, even on the same server, we respect cpu_count (eg you can lower it) to do things like instance caging (ie, not let a particular instance consume all of the available resources).

http://www.oracle.com/technetwork/database/performance/instance-caging-wp-166854.pdf

https://docs.oracle.com/database/121/REFRN/GUID-78CDCDE7-5A1D-4AC1-B5BD-B185CB296416.htm#REFRN10023

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A reader, February 05, 2017 - 7:43 pm UTC


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