oracle数据库优化辅助SQL语句

--查询正在执行的SQL语句


SELECT OSUSER 电脑登录身份, 
PROGRAM 发起请求的程序, 
USERNAME 登录系统的用户名, 
SCHEMANAME, 
B.Cpu_Time 花费cpu的时间, 
STATUS, 
B.SQL_TEXT 执行的sql,
B. 
FROM V$SESSION A 
LEFT JOIN V$SQL B ON A.SQL_ADDRESS = B.ADDRESS 
AND A.SQL_HASH_VALUE = B.HASH_VALUE 
ORDER BY b.cpu_time DESC;


--查询比较耗CPU的SQL语句
select *
from (select v.sql_id,
v.child_number,
v.sql_text,
v.elapsed_time,
v.cpu_time,
v.disk_reads,
rank() over(order by v.cpu_time desc) elapsed_rank
from v$sql v) a
where elapsed_rank <= 10;

--查询比较耗磁盘的SQL语句

select * from (select v.sql_id,
v.child_number, v.sql_text, 
v.elapsed_time, v.cpu_time, 
v.disk_reads, 
rank() over(order by v.disk_reads desc) elapsed_rank 
from v$sql v) a where elapsed_rank <= 10;

--查询比较慢的SQL语句

select * from (
select parsing_user_id,executions,sorts
command_type,disk_reads,sql_text from v$sqlarea order by disk_reads desc
)where rownum<10

--Oracle 对未提交事务的查询

select a.sid,a.blocking_session,a.last_call_et,a.event,
object_name,
dbms_rowid.rowid_create(1,data_object_id,rfile#,ROW_WAIT_BLOCK#,ROW_WAIT_ROW#) "rowid" ,
c.sql_text,c.sql_fulltext
from v$session a,v$sqlarea c ,dba_objects,v$datafile
where a.blocking_session is not null
and a.sql_hash_value = c.hash_value 
and ROW_WAIT_OBJ#=object_id and file#=ROW_WAIT_FILE#;

SELECT LOC_ID , LOC_DESC , REGION

FROM LOCATION

WHERE LOC_ID = 10

UNION

SELECT LOC_ID , LOC_DESC , REGION

FROM LOCATION

WHERE REGION = “MELBOURNE”

SELECT LOC_ID , LOC_DESC , REGION

FROM LOCATION

WHERE LOC_ID = 10 OR REGION = “MELBOURNE”