Re: PCTUSED & PCTFREE Q's

JP,

Actually 'pctfree' is the factor which is set aside in each datablock for future updates . Oracle does data stores in the block then based upon the row length, 'pctused' on the otherhand is the parameter which determines the threshold at which time a block that has reached its pctfree, will become available to store more data. e.g.

If a table has a pctfree of 15 and pctused set to 80, Oracle will stop storing data when it has 15% free space, when and if the data is deleted so as to make the space used to 80% or less ( that will make the pctfree 20%) , the rdbms will then store data in the block.

In effect at the time the threshold of 15% free space is reached, the status of the block is switched from available to un-available ( in the free block list).

This status is only changed when the data used % falls below 80% ( in my example). This addition of data in a block occurs until only 15% of space is left free.

Hopes this helps.

Vikram Goel

MOTOROLA - Byonton Beach, FL

email: vgoel_at_emi.net Received on Mon Oct 30 1995 - 00:00:00 CET