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Home -> Community -> Mailing Lists -> Oracle-L -> RE: automatic segment space management
We used this method (I wish I had come up with the Goldilocks code name...)
in 8.0.4 on a couple of data warehouses. The bottom line is that we had 1
space related failure (application code filled up the error log) in over 9
months of operation. Which so impressed management that they decided to cut
the support budget (not enough outages/calls to help desk).
There were over 150 tablespaces per database so we could perform I/O balancing, object segregation, etc. We did not follow the SAFE (3 and only 3 extent sizes in the database). Rather we used 3 extent sizes per tablespace with medium a multiple of small and large a multiple of medium.
PCTFREE - set to 10 (no updates, but provided a little space just in case
this changed)
PCTUSED - set to 80 (same reason as above)
FREELIST - set to 5 (originally designed so only 2 processes would ever
concurrently insert data)
Sounds like you are on the right track.
-----Original Message-----
Sent: Tuesday, September 03, 2002 9:49 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 - 12:48:25 CDT
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