1.查詢DB表實際大小(保證clob/blob/nclob lob大字段)
select round(sum(bytes/1024/1024/1024),2) ||'G' from dba_segments where owner='用戶' and segment_name ='表' OR segment_name IN (select SEGMENT_NAME from dba_LOBS where TABLE_NAME='表' and owner='用戶');
如果不是dba用戶可以用user_segments & user_lobs 且不需要owner.
2. 查詢表裏LOB大字段
select round(sum(b.BYTES/1024/1024),2) ||'M' from dba_lobs a, dba_segments b where a.segment_name = b.segment_name and a.owner = '用戶(大寫)' and a.table_name = '表(大寫)' ;
3.查詢表大小不帶LOB大字段
select round(sum(bytes/1024/1024/1024),2) ||'G' from user_segments where segment_name ='表';
4.表數據被刪除
a. 若表的數據被truncate,上述方法查到的數據會立即變化
b. 若表的數據被delete,則需要對錶進行收縮,上述查詢纔會變化;
alter table 表名 enable row movement; alter table 表名 shrink space;