oracle性能sql

查出锁定object的session的信息以及被锁定的object名

SELECT L.SESSION_ID SID,
S.SERIAL#,
L.LOCKED_MODE,
L.ORACLE_USERNAME,
L.OS_USER_NAME,
S.MACHINE,
S.TERMINAL,
O.OBJECT_NAME,
S.LOGON_TIME
FROM V$LOCKED_OBJECT L, ALL_OBJECTS O, V$SESSION S
WHERE L.OBJECT_ID = O.OBJECT_ID
AND L.SESSION_ID = S.SID
ORDER BY SID, S.SERIAL#;

查出锁定表的session的sid, serial#,os_user_name, machine name, terminal和执行的语句

SELECT L.SESSION_ID SID,
S.SERIAL#,
L.LOCKED_MODE,
L.ORACLE_USERNAME,
S.USER#,
L.OS_USER_NAME,
S.MACHINE,
S.TERMINAL,
A.SQL_TEXT,
A.ACTION
FROM V$SQLAREA A, V$SESSION S, V$LOCKED_OBJECT L
WHERE L.SESSION_ID = S.SID
AND S.PREV_SQL_ADDR = A.ADDRESS
ORDER BY SID, S.SERIAL#;

解锁表

--kill session语句
--'151,3027'格式：'SID,SERIAL#'
ALTER SYSTEM KILL SESSION '61,563';

查询正在执行的sql

SELECT b.sid oracleID,
b.username,
b.serial#,
spid,
paddr,
sql_text,
b.machine
FROM v$process a, v$session b, v$sqlarea c
WHERE a.addr = b.paddr AND b.sql_hash_value = c.hash_value;

查看占io较大的正在运行的session

SELECT se.sid,
se.serial#,
pr.SPID,
se.username,
se.status,
se.terminal,
se.program,
se.MODULE,
se.sql_address,
st.event,
st. p1text,
si.physical_reads,
si.block_changes
FROM v$session se, v$session_wait st, v$sess_io si, v$process pr
WHERE st.sid = se.sid
AND st. sid = si.sid
AND se.PADDR = pr.ADDR
AND se.sid > 6
AND st. wait_time = 0
AND st.event NOT LIKE '%SQL%'
ORDER BY physical_reads DESC;

查找前十条性能差的sql

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;

从V$SQLAREA中查询最占用资源的查询

select b.username username,a.disk_reads reads,a.BUFFER_GETS as buffer,
a.executions exec,a.disk_reads/decode(a.executions,0,1,a.executions) rds_exec_ratio,
a.sql_text Statement
from v$sqlarea a,dba_users b
where a.parsing_user_id=b.user_id
and a.disk_reads > 100000
order by a.disk_reads desc;

列出使用频率最高的5个查询

select sql_text,executions
from (select sql_text,executions,
rank() over
(order by executions desc) exec_rank
from v$sql)
where exec_rank <=5;

消耗磁盘读取最多的sql top5

select disk_reads,sql_text
from (select sql_text,disk_reads,
dense_rank() over
(order by disk_reads desc) disk_reads_rank
from v$sql)
where disk_reads_rank <=5;

找出需要大量缓冲读取（逻辑读）操作的查询

select buffer_gets,sql_text
from (select sql_text,buffer_gets,
dense_rank() over
(order by buffer_gets desc) buffer_gets_rank
from v$sql)
where buffer_gets_rank<=5;

查询负载
SELECT *
FROM ( SELECT A.INSTANCE_NUMBER,
A.SNAP_ID,
B.BEGIN_INTERVAL_TIME + 0 BEGIN_TIME,
B.END_INTERVAL_TIME + 0 END_TIME,
ROUND(VALUE - LAG( VALUE, 1 , '0')
OVER(ORDER BY A.INSTANCE_NUMBER, A.SNAP_ID)) "DB TIME"
FROM (SELECT B.SNAP_ID,
INSTANCE_NUMBER,
SUM(VALUE ) / 1000000 / 60 VALUE
FROM DBA_HIST_SYS_TIME_MODEL B
WHERE B.DBID = (SELECT DBID FROM V$DATABASE)
AND UPPER (B.STAT_NAME) IN UPPER(('DB TIME' ))
GROUP BY B.SNAP_ID, INSTANCE_NUMBER) A,
DBA_HIST_SNAPSHOT B
WHERE A.SNAP_ID = B.SNAP_ID
AND B.DBID = (SELECT DBID FROM V$DATABASE)
AND B.INSTANCE_NUMBER = A.INSTANCE_NUMBER)
WHERE TO_CHAR(BEGIN_TIME, 'YYYY-MM-DD') = TO_CHAR(SYSDATE , 'YYYY-MM-DD')
ORDER BY BEGIN_TIME;