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Home -> Community -> Mailing Lists -> Oracle-L -> RE: automatic segment space management
Rachel - I have been using LMTs with uniform extents (Oracle-recommended
variation) for a couple of years now with Oracle 8.1.6, and now 9.2. The
Oracle-recommended extent sizes are 128k, 4m, and 128m. As far as PCTFREE,
et. al., these are at the table level, so my opinion would be that the
guidelines for these are unchanged from the pre-LMT days. The key issue with
the highly updated customer table would be whether the size of the row is
changing. If you can keep the row size constant, then you won't wind up with
chained rows. The biggest issue facing you is whether you turn AUTOEXTEND
on. I did that and have encountered relatively few problems. Well, one
problem. I had tables set with large NEXT extents to minimize extents, and
when one extended boy did my sys admin get excited. I changed that.
A bigger issue in building your data warehouse is whether you can use the partitioning option. Most of our queries were taking more than 2 minutes and I was able to partition and bring that down below 10 seconds. The users were pretty excited.
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-----Original Message-----
Sent: Tuesday, September 03, 2002 10:49 AM
To: Multiple recipients of list ORACLE-L
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
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).
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 - 12:42:15 CDT
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