DBA_TABLES之BLOCKS AND EMPTY_BLOCKS

SQL> select owner,table_name,blocks,EMPTY_BLOCKS from dba_tables where EMPTY_BLOCKS <>0;

OWNER                          TABLE_NAME                         BLOCKS EMPTY_BLOCKS
------------------------------ ------------------------------ ---------- ------------
SCOTT                          TEST_1                             245550         1106

用show_space查看
Total Blocks  ..........................246656
Total Bytes   ..........................2020605952
Total MBytes  ..........................1927
Unused Blocks ..........................1106
Unused Bytes  ..........................9060352
Unused KBytes ..........................8848
Used Blocks   ..........................245550
Used Bytes    ..........................2011545600
Used KBytes   ..........................1964400
Last Used Ext FileId....................4
Last Used Ext BlockId...................376704
Last Used Block.........................7086


BLOCKS*	NUMBER	
Number of used data blocks in the table
EMPTY_BLOCKS*	NUMBER	
Number of empty (never used) data blocks in the table



BLOCKS 列代表该表中曾经使用过得数据库块的数目，即水线。
EMPTY_BLOCKS 代表分配给该表，但是在水线以上的数据库块，即从来没有使用的数据块