Re: partitioning question 1

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От Ben
Тема Re: partitioning question 1
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Msg-id 59555E0F-71C2-4062-AD23-F1B7B9993354@gmail.com
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Ответ на Re: partitioning question 1  ("Igor Neyman" <ineyman@perceptron.com>)
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On Oct 29, 2010, at 7:38 AM, Igor Neyman wrote:

>> is my intuition completely off on this?
>>
>> best regards, ben
>>
>
> If your SELECT retrieves substantial amount of records, table scan could
> be more efficient than index access.
>
> Now, if while retrieving large amount of records "WHERE clause" of this
> SELECT still satisfies constraints on some partition(s), then obviously
> one (or few) partition scans will be more efficient than full table scan
> of non-partitioned table.
>
> So, yes partitioning provides performance improvements, not only
> maintenance convenience.

my impression was that a *clustered* index would give a lot of the same I/O benefits, in a more flexible way.  if
you'reclustered on the column in question, then an index scan for a range is much like a sequential scan over a
partition(as far as i understand.) 

b

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