show_space 查詢表資料塊碎片問題 - show_space 結果解釋 7

例項 ：  
SQL> set serveroutput on 
SQL> exec  show_space('HWCUST_ICSP_AGREEMENT_T','TABLE','AUTO','Y', NULL,'HWCUST') ;  

---- 以下由DBMS_SPACE.UNUSED_SPACE輸出 
Total Blocks............................256     ---- 分配給object的總的blocks(高水位線上下的) 
Total Bytes.............................2097152
Unused Blocks...........................128     ---- 分配了但是未被使用的Blocks，shrink能夠釋放的空間 
Unused Bytes............................1048576 ---- HWM=total blocks-unused blocks. 這種計算得到的結果應該是high HWM的值。
Last Used Ext FileId....................4144    ---- Returns the file ID of the last extent which contains data
Last Used Ext BlockId...................807424  ---- Returns the starting block ID of the last extent which contains data 
Last Used Block.........................128     ---- Returns the last block within this extent which contains data
---- 以下由 DBMS_SPACE.SPACE_USAGE 輸出 
Thesegment is analyzed                        
0% -- 25% free space blocks..............0
0% -- 25% free space bytes...............0
25% -- 50% free space blocks.............0
25% -- 50% free space bytes..............0
50% -- 75% free space blocks.............0
50% -- 75% free space bytes..............0
75% -- 100% free space blocks............31
75% -- 100% free space bytes.............253952
Unused (unformatted) Blocks...........................90
Unused (unformatted) Bytes............................737280
Total Blocks (100%)............................1 
Total bytes (100%).............................8192
PL/SQL procedure successfully completed.
SQL>