Re: why CTAS faster than Insert select?

linda wrote:
>
> Hi,
>
> I've been testing the performance between Create Table As Select (CTAS)
> vs Insert Select for large volume of data (40 million records or so).
> Both in nologging mode, parallel, etc. It consistently shows that CTAS
> faster than Insert Select. My understanding is that, if you parallel
> both create/insert process and select process, then theoratically they
> should perform about the same (same amount of work, same number of
> parallel processes, minimum redo and undo...). Could anybody explain
> why this is the case?
>
> Thanks,
> Linda

Try

insert /*+ APPEND */

hth
connor

-- 
Connor McDonald
Co-author: "Mastering Oracle PL/SQL - Practical Solutions"
Co-author: "Oracle Insight - Tales of the OakTable"

web: http://www.oracledba.co.uk
web: http://www.oaktable.net
email: connor_mcdonald_at_yahoo.com


"GIVE a man a fish and he will eat for a day. But TEACH him how to fish,
and...he will sit in a boat and drink beer all day"

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