如何查看ORACLE空间占用问题

最近，项目上ORACLE数据库越来越大，需要查看下数据库数据量占用大的原因。

1、查看ORACLE表空间及表数据大小

Select Segment_Name,Sum(bytes)/1024/1024 From User_Extents group By Segment_Name order by Sum(bytes)/1024/1024 desc;

2、从返回的结果看，有一个segment名为"SYS_LOB0000053810C00004$$"的对象占用了大量的空间;即LOB(BLOB和CLOB)对象占用的大小对象

3、根据segment_name，就可以从 dba_lobs 表里查到是哪个表，哪个字段;

select * from dba_lobs where segment_name like 'your_segment_name';

里面显示的TABLE_NAME和COLUMN_NAME为表名和字段名。

 

set pagesize 200  

column "数据文件名称" format a25  

column "表空间名称"   format a18  

column "容量(M)"  format a12  

column "使用率%"  format a12  

column "最大容量(M)" format a15  

column "可扩充容量(M)" format a15  

column "空闲(M)" format a12  

column "自动扩展" format a10  

select a.FILE_NAME "数据文件名称",a.TABLESPACE_NAME"表空间名称",  

to_char(100-round((nvl(b.free_bytes,0)/a.BYTES)*100,2)) "使用率%",  

to_char(round(a.BYTES/1024/1024,2)) "容量(M)",  

to_char(round(nvl(b.free_bytes,0)/1024/1024,2)) "空闲(M)",  

to_char(round(decode(a.autoextensible,'YES',a.maxbytes/1024/1024,'NO',a.bytes/1024/1024),2)) "最大容量(M)",  

a.autoextensible "自动扩展",  

to_char(round(decode(a.autoextensible,'YES',a.maxbytes/1024/1024,'NO',a.bytes/1024/1024)-a.BYTES/1024/1024,2)) "可扩充容量(M)" 

from dba_data_files a,  

(select FILE_ID,sum(bytes) free_bytes from dba_free_space group by FILE_ID) b  

where a.FILE_ID=b.FILE_ID  

order by to_number("可扩充容量(M)") asc;