Re: Interview question
- From: Guillermo Alan Bort <cicciuxdba@xxxxxxxxx>
- To: raju raju <rajugaru.vij@xxxxxxxxx>
- Date: Fri, 26 Apr 2013 12:10:37 -0300
Partitioning?
Adding a column and flagging the rows is not the same as removing them. So
this is a functional question. If the app supports the use of this column
to filter the rows then you would be adding a fast full index scan to the
execution of the queries (assuming they are written properly). However,
removing them would have a big impact for a limited time and no execution
plan would need to change. I would personally go with deleting the records,
under the correct circumstances, of course.
A deeper understanding of the relation between these tables and the reason
behind the data duplication would be necessary.
hth
Alan.-
On Fri, Apr 26, 2013 at 10:36 AM, <rajugaru.vij@xxxxxxxxx> wrote:
> Again back with an interview question.
> Table A has 400 million rows and table b has 1 million rows.
>
> I want to compare table A and Table B and find all the rows available in b
> which are already available in A.
>
> want to remove all those which are available in B from A.
>
> What would be best option? Deleting them or adding a column and flagging
> them?
>
> What's the better option performance wise?
>
> Thanks
> Sent on my BlackBerry® from Vodafone--
> //www.freelists.org/webpage/oracle-l
>
>
>
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