Re: about pct_free avg_space

>> Name : PROCP
>> blocks : 11832
>> num_rows : 50008
>> avg_row_len : 998
>> avg_space : 3826
>> size (blocks*8) : 92.44Mo
>> size (num_rows*avg_row_len) : 47.6Mo
>>
>> So why the blocks are not more used, they are ~50% Full ?
>>

>How did you arrive at this determination? avg_space reports the
>AVERAGE free space over all of the populated data blocks, and the
>number of blocks the table consumes is a function of many things,
>including the initial and next extent sizes as well as the PCTFREE and
>PCTUSED values. How have you determined, for each block, it's percent
>population?

Well i've just made blocks*8192 / num_rows*avg_row_len And based on the fact that when pctfree is 0, there are only 6545 blocks and when pctfree 10 there are 11832 blocks I assumed that the block are roughly 50% full Maybe this is not the good way but this is not the only table in the database who is in this case.

But if i understand your statement that "avg_space reports the AVERAGE free space over all of the populated data blocks" In my case, the avg_space is 3826/8192 for all used blocks and that means 46% free space for all used blocks

>
>> I have created a copy of this table with pctfree 0, here it seems correct
>> to
>> me, the block are full
>> Name : PROCP_pctfree0
>> blocks : 6545
>> num_rows : 50008
>> avg_row_len : 998
>> avg_space : 410
>> size (blocks*8) : 51.13Mo
>> size (num_rows*avg_row_len) : 47.6Mo
>>
>> and another one with pctfree 30
>> Name : PROCP_pctfree30
>> blocks : 12379
>> num_rows : 50008
>> avg_row_len : 998
>> avg_space : 4012
>> size (blocks*8) : 96.71Mo
>> size (num_rows*avg_row_len) : 47.6Mo
>>
>> Any idea ?
>>
>
>Again, how did you determine, for each block, the percent data
>population?

same as above

>
>> ps: The segment management is manual, i have tested with auto and it's
>> the
>> same values
>>
>> thanks
>
>
>David Fitzjarrell
Received on Mon Mar 31 2008 - 10:18:12 CDT