DBA巡檢經常使用的SQL語句

1.查看當前數據庫有多少process

select count(1) from v$process;

2.查看當前數據庫有多少session(session=process*1.1)

select count(1) from v$session;

3.查看當前執行的SQL語句

select a.program,b.spid,c.sql_text,c.sql_id from v$session a,v$process b,v$sqlarea c where a.paddr=b.addr and a.sql_hash_value=c.hash_value;       --若是SQL語句沒有顯示完就執行下面語句

select a.* from v$sql a where a.SQL_ID='686nqabc8sgs2'    --686nqabc8sgs2爲上面語句的sql_id

4.查看錶空間名稱及大小

select t.tablespace_name, round(SUM(bytes/(1024 * 1024)),0) ts_size from dba_tablespaces t, dba_data_files d where t.tablespace_name = d.tablespace_name group by t.tablespace_name;

--顯示錶空間名和表空間大小,大小是多少M.

5. 計算表空間數據文件使用狀況

select a.tablespace_name, total, free, total-free as used from (select tablespace_name, sum(bytes)/1024/1024 as total from dba_data_files group by tablespace_name) a,(select tablespace_name, sum(bytes)/1024/1024 as free from dba_free_space group by tablespace_name) b where a.tablespace_name = b.tablespace_name;

6.查看臨時表空間的使用率

select * from v$temp_space_header;

7.查看當前oracle用戶的會話數

select username,count(username) from v$session where username is not null group by username;

8.查詢表中某行在哪一個數據文件

select a,rowid,dbms_rowid.rowid_relative_fno(rowid) || '_' || dbms_rowid.rowid_block_number(rowid) || '_' || dbms_rowid.rowid_row_number(rowid) as f_b_n from t where a=4;
A           ROWID           F_B_N
4    AAAUCYAABAAAXEpAAB       1_94505_1      --1表示第1個數據文件,94505表示第多少個塊,1表示數據在表中每2行,由於每1行是0

9.經過sql_id找用戶的id值

select distinct USER_ID from dba_hist_active_sess_history where sql_id='44u0yksh36aq2';

10.經過user_id查找用戶

select user_id,username from dba_users where user_id=98;