Re: By default, LOB store in line or out of line?

From: Leyi Kamus Zhang <kamusis_at_gmail.com>
Date: Mon, 23 Apr 2012 22:17:41 +0800
Message-ID: <CAPtFprqdXN=++TYNbewXgMkh6=+WwOkrHf7zWykvHTp1_xtSZA_at_mail.gmail.com>

Hi, Fairlie
Our test is with 8 concurrent sessions CTAS over dblink, we transfered 7TB LOB in 64 hours with "as of scn" flashback query from source database.

Yours 12 concurrent jobs in 9 hours transfered 500GB data or 13TB? I also tested insert /+*append parallel*/, but the result is far worse than CTAS. Can you share your test result? Did you test CTAS?

Our migration is painful... the source database has a single table over 7TB, almost LOB, no partition, actively inserted and updated, we have to use WHERE condition to split the source table into little pieces and have to use flashback query to get the consistency. The worst experience was after 20 hours CTAS we got ORA-01555 error, even we have set the UNDO RETENTION for LOB to 48 hours.

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On Mon, Apr 23, 2012 at 7:10 PM, fairlie rego <fairlie_r_at_yahoo.com> wrote:



> Approach 2

> ---------

> Insert over a dblink by having 12 concurrent scheduler jobs each working

> on discrete data (as outlined by Tanel below) took less than 9 hours.

>



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Received on Mon Apr 23 2012 - 09:17:41 CDT