Re: Data Migration options - oracle to oracle

From: Norman Dunbar <>
Date: Fri, 06 Sep 2013 16:23:14 +0100
Message-ID: <>

Hi Raj,

On 06/09/13 15:38, rjamya wrote:
> Correction to correction ... please read that as follows
> if I may, based on _my_ experience, expdp seems to export tables from
> largest to smallest. I am yet to see it alphabetical in 10g/11g. Dont
> have 12c so that is a unknown for me.

Thanks for that, I appreciate it. I've honestly never noticed it being anything other than alphabetical, but I'm only using it on 11g at the moment. I have 12c ready to install. However, I shall do a test at some point. I wonder if it is because the PARALLEL parameter is in use? I would assume that that would cause there to be a master process and 'n' worker processes, all exporting to their own unique dump file (%U in the name). I need to test this!

However, your comment made me hit the 11g docs, and I found something else I didn't know:

Data Pump does not load tables with disabled unique indexes. To load data into the table, the indexes must be either dropped or re-enabled.

So that's one for the "to note" page in my book!

[insert delay here]

Ok, I'm back. I tested with parallel = 1 and exported a user at schema level, with expdp. I got a non-alphabetic listing! So your were correct, expdp doesn't do it alphabetically. Thanks.

However, I saw that the log produced didn't appear to have any order to it at all, there were zero row tables exported that were bigger and smaller than some that followed. So it's not based on row numbers or table size as far as I can see.

With parallel=2 I saw the nice ordered sequence of "processing object ...." followed by the "exporting ....." messages, interspersed. Lots of "exporting..." and a few "processing..." messages all randomly mixed up.

So, I stand corrected on the alphabetic point I made, thank you very much. As for the order it decides? Who knows. Maybe it's related to how the objects names come back in a "select table_name from user_tables" perhaps? (No, it's not - I tried that too!)

Thanks again.


Norman Dunbar
Dunbar IT Consultants Ltd

Registered address:
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Received on Fri Sep 06 2013 - 17:23:14 CEST

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