标题: oracle回收表空间文件大小 [打印本页] 作者: 王亮 时间: 2021-1-24 17:03 标题: oracle回收表空间文件大小 1、查看表空间的使用情况：
select a.tablespace_name,a.bytes/1024/1024 "Sum MB",(a.bytes-b.bytes)/1024/1024 "used MB",b.bytes/1024/1024 "free MB",
round(((a.bytes-b.bytes)/a.bytes)*100,2) "percent_used"
from
(select tablespace_name,sum(bytes) bytes from dba_data_files group by tablespace_name) a,
(select tablespace_name,sum(bytes) bytes,max(bytes) largest from dba_free_space group by tablespace_name) b
where a.tablespace_name=b.tablespace_name
order by ((a.bytes-b.bytes)/a.bytes) desc；
2、使用SQL生成回收表空间文件的命令：
select 'alter database datafile '''||a.file_name||''' resize ' ||round(a.filesize - (a.filesize - c.hwmsize-100) *0.8)||'M;',
a.filesize,c.hwmsize
from ( select file_id,file_name,round(bytes/1024/1024) filesize from dba_data_files ) a,
( select file_id,round(max(block_id)*8/1024) HWMsize from dba_extents group by file_id) c
where a.file_id = c.file_id and a.filesize - c.hwmsize > 100；