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Home > Archive > ASE Database forum > October 2005 > Clustered vs. Nonclustered
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Clustered vs. Nonclustered
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| R Garces 2005-10-27, 8:21 am |
| Hi !
I have a table with 50 millions of records and created with
LOCK DATAROWS schema
I am thinking to change the CLUSTERED index for a
NONCLUSTERED index for convert this table a HEAP TABLE (it
has 3 nonclustered index).
In this case, the INSERT'S operations will be faster? (I
have a lot INSERT's on this table in on-line and batch mode)
Thanks !
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| Bret Halford 2005-10-27, 8:21 am |
| It might, if the clustered index is causing a lot of writes
to uncached pages. However, if most of the table's pages
are resident in cache, I wouldn't expect much difference.
On the other hand, if you force all the writes to the same
device, you might saturate that device and actually decrease
performance.
-bret
R, Garces wrote:
> Hi !
>
> I have a table with 50 millions of records and created with
> LOCK DATAROWS schema
>
> I am thinking to change the CLUSTERED index for a
> NONCLUSTERED index for convert this table a HEAP TABLE (it
> has 3 nonclustered index).
>
> In this case, the INSERT'S operations will be faster? (I
> have a lot INSERT's on this table in on-line and batch mode)
>
> Thanks !
| |
| R Garces 2005-10-27, 8:21 am |
| Thanks Bret !
About your answer, if I alter the table and applicate
PARTITIONS Will I avoid to write in only one device and then
the programs will write in ramdom devices?
> It might, if the clustered index is causing a lot of
> writes to uncached pages. However, if most of the table's
> pages are resident in cache, I wouldn't expect much
> difference. On the other hand, if you force all the writes
> to the same device, you might saturate that device and
> actually decrease performance.
>
> -bret
>
> R, Garces wrote:
>
> batch mode) >
>
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| Jeffrey R. Garbus 2005-10-27, 5:29 pm |
| You'll get multiple page chains; whether you avoid device saturation will
depend upon whether you also have multiple physical devices. Many shops use
SANs now, making this nontrivial to determine.
<R Garces> wrote in message news:4356b131.7439.1681692777@sybase.com...[color=darkred]
> Thanks Bret !
>
> About your answer, if I alter the table and applicate
> PARTITIONS Will I avoid to write in only one device and then
> the programs will write in ramdom devices?
>
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