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Home -> Community -> Mailing Lists -> Oracle-L -> RE: PCTFREE and PCTUSED
PCTUSED comes into play when rows are deleted from the block. If enough
data is deleted from a block to cause the block to fall below 60% used
(PCTUSED), the block goes back on the freelist for subsequent
inserts/updates.
-----Original Message-----
Sent: Tuesday, November 04, 2003 3:09 PM
To: Multiple recipients of list ORACLE-L
Suppose I have the following settings which happen to be the defaults as well:
PCTFREE 10
PCTUSED 40
I am trying to figure out what PCTUSED is really used for.
My book is telling me that is used so that Oracle knows
whether to keep a block in the "free-list".
My point is this: If PCTFREE is 10%, that means the block can be up to 90% full, right?
Well, if the block happens to be 60% full at the moment, then Oracle knows that this block is not full enough because 60 is less than 90, so it can keep it in the free list. I dont see what PCTUSED is needed, it kind of seems I can accomplish the same with just one parm, that being PCTFREE. But Oracle wouldnt have just put a parm there without any usage, so I guess there's something I dont see...
Any ideas/examples? Any good reasoning anywhere?
Thanks,
maa
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Please see the official ORACLE-L FAQ: http://www.orafaq.net
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Author: Maryann Atkinson
INET: maryann_30_at_yahoo.com
Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services ---------------------------------------------------------------------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 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services ---------------------------------------------------------------------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 Nov 04 2003 - 17:19:26 CST
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