1. 查看表空间大小：
SELECT tablespace_name, SUM(bytes)/1024/1024 total FROM DBA_FREE_SPACE GROUP BY tablespace_name ORDER BY 2 DESC;

SQL> SELECT tablespace_name, SUM(bytes)/1024/1024 || 'MB' total FROM DBA_FREE_SPACE GROUP BY tablespace_name ORDER BY 2 DESC;

注意下上面两条SQL的排序，显然第一条SQL是我们需要的结果，按照表空间大小降序排列。之所以第二条SQL的排序乱，是因为使用了|| 'MB'连接字符串，则这个字段就作为字符串类型检索，排序时就会按照字符的ASCII进行排序。

2. 查看表空间使用率：

SQL> BREAK ON REPORT

SQL> COMPUT SUM OF tbsp_size ON REPORT

SQL> compute SUM OF used ON REPORT

SQL> compute SUM OF free ON REPORT

SQL> COL tbspname FORMAT a20 HEADING 'Tablespace Name'

SQL> COL tbsp_size FORMAT 999,999 HEADING 'Size|(MB)'

SQL> COL used FORMAT 999,999 HEADING 'Used|(MB)'

SQL> COL free FORMAT 999,999 HEADING 'Free|(MB)'

SQL> COL pct_used FORMAT 999,999 HEADING '% Used'

SQL> SELECT df.tablespace_name tbspname,

sum(df.bytes)/1024/1024 tbsp_size,

nvl(sum(e.used_bytes)/1024/1024,0) used,

nvl(sum(f.free_bytes)/1024/1024,0) free,

nvl((sum(e.used_bytes)*100)/sum(df.bytes),0) pct_used

FROM DBA_DATA_FILES df,

(SELECT file_id, SUM(nvl(bytes, 0)) used_bytes

FROM dba_extents

GROUP BY file_id) e,

(SELECT MAX(bytes) free_bytes, file_id

FROM dba_free_space

GROUP BY file_id) f

WHERE e.file_id(+) = df.file_id

AND df.file_id = f.file_id(+)

GROUP BY df.tablespace_name

ORDER BY 5 DESC;

视图定义：

ITPub博客

查看表空间使用的两条常用SQL