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Home -> Community -> Mailing Lists -> Oracle-L -> Re: automatic segment space management
Ron,
yes it helps, thanks! I forgot to mention that I will be using UNIFORM sizes for the LMTs, I don't really see the advantage to "autoallocate"
I can probably get away with the defaults for the parameters (if I don't use automatic segment space allocation) but it will waste some space in some of the tables.
We will be partitioning most of the fact tables by date (the date dimension key is going to be the numeric representation of the date that row has info on) but likely the customer fact table will be hash partitioned as we don't intend to ever prune that table.
Rachel
--- Ron Rogers <RROGERS_at_galottery.org> wrote:
> Rachel,
> You did not say if you would be using the UNIFORM option for the
> LMT's. If you allow the system to choose the initial sizing there can
> be
> a lot of wasted space as the table size grows. The system will choose
> sizing options that you most likely would not choose. I can't find my
> reference to the sizes that are chosen but 16K 64K 1M and 4M sound
> correct. The extends will increase as the total size of the table
> increases.
> I find it easier to manage the sizes of the tables in the tablespace
> with uniform extent sizes that are manageable and mist likely to be
> filled in a reasonable time frame. For small static tables I used a
> multiple of the block size and tried to group similarly used table in
> the same tablespace. The tables that are continually growing daily I
> partitioned by date range and allowed the tablespace to autoextend.
> There is very little wasted space and the tablespaces are usually 100
> %
> full until the next extent is needed.
> I accepted the default PCTFREE, PCTUSED and FREELIST parameters and
> I
> haven't seen and problems yet.
> I hope this helps,
> Ron
> ROR mª¿ªm
>
> >>> wisernet100_at_yahoo.com 09/03/02 11:48AM >>>
> time for me to ask the experts again.
>
> My data warehouse will be 9.2, with all locally managed tablespaces.
> We
> will be following what I have taken to calling the "Goldilocks"
> principle -- that of small, medium and large tablespace extent sizes,
> with variations in that we will separate indexes and data, and will
> have even more separation for our fact tables into partitioned tables
> and tablespaces.
>
> However, now comes the time for me to work out storage clauses. And a
> quick read through the docs leaves me wondering if I should just turn
> on automatic segment-space management and not worry about setting
> PCTFREE, PCTUSED and FREELIST parameters. I can't find any real
> information or bugs on MetaLink either.
>
> Does anyone have any experience, good OR bad, with using this
> feature?
> If you are doing data warehouse work, what are good values for the
> parameters if I DO use them? One fact table is likely to be highly
> updated (customer info) as we collect more and more specific
> information from customers. The rest will be, as you would expect
> from
> a DW, mostly inserts.
>
> Help?
>
> Thanks!
>
> Rachel
>
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> Please see the official ORACLE-L FAQ: http://www.orafaq.com
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> Author: Rachel Carmichael
> INET: wisernet100_at_yahoo.com
>
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> Author: Ron Rogers
> INET: RROGERS_at_galottery.org
>
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-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Rachel Carmichael INET: wisernet100_at_yahoo.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Tue Sep 03 2002 - 13:48:36 CDT
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