PCTFREE and PCTUSED

[juniordbam]

Sorry for stupid question, but I'm confused......
I want to calculate PCTFREE and PCTUSED with the following formulas:
PCTFREE=(average row size -initial row size)*100/average row size
PCTUSED=average row size*100/available data space

But here I don't understand how to obtain average row size ,initial row size and available data space.
Please, explain.

[jkoopmann]

both the average row size and initial row size are "what" you expect the initial insert of data for a row to be and then the average row size is "what" you expect the row to look like after all updates have been done to the row. so if you were to insert a row in a table where the total bytes in the row never changed , the initial row size and average row size would not change and you would use a PCTFREE of zero.

the available data space is more than likely the size of you data block.

i personally don't know if there is a valid calculation for PCTUSED since it is more of a factor of what you can "deal" with and how quickly you want the data block to be placed back on the free list. i would suggest switching over to auto segment space management option and not worry about this parameter. take a look at an article i wrote http://www.databasejournal.com/featu...le.php/1576991

[juniordbam]

Thank you very much!!!!!
Please give me the full link or your article name.

[jkoopmann]

you should be able to click on it but here it is again.

http://www.databasejournal.com/features/oracle/article.php/1576991