RE: Should each partition have it's own tablespace and

A little off topic from the subject line -

I admit I have not even tried to RTFM on this. If you have each partition of a table in a seperate TS, what would happen if you wanted to MERGE the partitions? Would Oracle merge the TS? I don't use them, and am not going to either:) Just curious..

Cheers

Mark

-----Original Message-----
Sent: Thursday, April 12, 2001 01:46
To: Multiple recipients of list ORACLE-L

Hmmm, it depends on the situation. There are pros and cons in both, but certainly partitions should be in partitions-only tablespaces.

Unless you can size the partitions with great accuracy, you would have to build in reasonably free-space in the TBS. If you have overdone this, you would have to come back and resize. This would be a very tedious way of managing 100 tablespaces.

If you group the partitions in some logical manner, you can put them in the same TBS, and pool the free-space to allow for un-predicted growth, and minimise waste.

I am unclear why exp/imp is going to free up more space than dropping partitions, unless its severely fragmented. Keeping to uniform extents will get rid of this problem.

>>> kirti.deshpande_at_verizon.com 04/12/01 08:12AM >>>
Hi Cherie,
 I am in favor of one tablespace per partition. For availablity and maintenance purposes it certainly helps us in our environment. I have implemented this concept in our data mart database which is is now around 90GB. There are multiple datafiles per tablepace each representing an extent (~500 MB). We load data to this database once a month, so I am not too concerned with the checkpoint times etc. (due to a number of data files). There are 4 large tables with 10 partitions so far (one per year). Each table has 2-3 indexes, all locally partitioned. Again each in its own tablespace. Partitioning key is the 4 digit year. All tablespaces and partition names contain the 2 digit year for ease of understanding what's in them. Partitioned table data and partitioned index data is placed on physically separate storage devices. Since, all the data comes from other legacy (or otherwise, internal) systems, we do not have a partition for 'MAXVALUE', and that saves me a lot of work when adding new partitions for new years (did that for 2000 and 2001). Working very well for the last 2 years now, started out with 8.0 and recently upgraded to 8.1.7. All this was done as a parallel process and soon (next month) it will all be 'real' production with one more set of storage devices to split data and index further.

HTH..

• Kirti Deshpande Verizon Information Services http://www.superpages.com

> -----Original Message-----
> From: Cherie_Machler_at_gelco.com [SMTP:Cherie_Machler_at_gelco.com]
> Sent: Wednesday, April 11, 2001 2:06 PM
> To: Multiple recipients of list ORACLE-L
> Subject: Should each partition have it's own tablespace and datafile?
>
>
> We have a 120 Gig datawarehouse that uses
> more than 100 date-based partitions. For financial
> and political reasons, we have run out of disk space
> to give this database as it continues in it's relentless
> growth.
>
> The developers have resigned themselves to purge
> out some of the old data and get rid of partitions that
> are more than two years old.
>
> We currently have about ten tablespaces that contain
> all of the data and indexes for this database. There is
> a small, medium, and large tablespace for data and
> for indexes plus some other specialized tablespaces
> by functionality.
>
> Anyway, dropping a couple dozen of these partitions
> is not going to be enough to free up some disk space
> for us. Instead we're going to have to export our data,
> drop the tablespaces, and recreate them as a smaller
> size and then reimport the data minus the dropped
> partitions.
>
> Since we're going to all of this work, I'm wondering
> if we should reorg these partitions by creating a tablespace
> for each partition and a single datafile for each tablespace.
> That way in the future, every time we want to drop a partition,
> it will be very easy to reclaim the disk space associated with
> that partition. I don't want to have to do these reorgs every
> month.
>
> How do most places physically lay out their partitions?
> What is the downside of having a datafile for each partition?
> Wasted space? Would a compromise be to assign
> six months worth of partitions to a single tablespace?
>
> We are currently on version 8.0.4 of Oracle on Sun Solaris 2.6
> but we will be upgrading soon to 8.1.7. Looks like I may need
> to reorg this before we can upgrade as we are rapidly running
> out of room.
>
> Thanks,
>
> Cherie Machler
> Gelco Information Network
>
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