dbms_space.free_blocks does not report correctly ?

From: Diego Cutrone <dcutrone_at_afip.gov.ar>
Date: Fri, 20 Apr 2001 12:44:45 -0700
Message-ID: <F001.002EE3A2.20010420124556@fatcity.com>

Hi list,
 

I'm checking space usage in some
objects.
 

<FONT face=Arial

size=2> Type            
Name                          

               
    TBlocks   Unused     Used 

FBlocks      HWM
<FONT face=Arial
size=2>TABLE          
FND_CONCURRENT_REQUESTS     
21,075       70     
  3,557   20,225       21,005

<FONT face=Arial
size=2>TABLE          
GL_BALANCES         
       
            

126,233      220     
125,987        4     126,013

 
 

I've used the following query to calculate Used blocks (I mean blocks where there're rows, at least one). SELECT COUNT(DISTINCT
SUBSTR(rowid,15,4)||SUBSTR(rowid,1,8)) FROM segment;  ---> "Used"
 

And I've used dbms_space.free_blocks to calculate "FBlocks".
And dbms_space.unused_blocks to calculate "Unused" (blocks above HWM), "TBlocks" (Total blocks of the object). And HWM=TBlocks-Unused
 

So, check this out
 

Table GL_BALANCES, I've got 126233 blocks and 220 blocks unused, so we can say that HWM is 126013 (126233-220). And I've got 125987 blocks with some data in them, so 126013-125987= 26 blocks. This means that these 26 blocks were used some time ago (because they are below HWM) but they're not holding any rows now. right? So here's my question:
    why does dbms_space.free_blocks

report only 4 blocks ?????
 
    that means that below HWM there

are 4 blocks that are candidate for inserts, what happened with the 26 blocks !??
    shouldn't it be reporting at

least 26 blocks ?
 
 

Please help me out with this.
Thanks
 
 
 
 
Received on Fri Apr 20 2001 - 14:44:45 CDT