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Oracle常用的诊断语句
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1.数据池命中率
--db_pool命中率(要求：95%左右)：
select 100 -
100 * ((select value from v$sysstat where name = ‘physical reads‘)) /
((select value from v$sysstat where name = ‘consistent gets‘) +
(select value from v$sysstat where name = ‘db block gets‘))
from dual;
select *
from V$PARAMETER
where name in (‘sga_max_size‘,
‘db_cache_size‘,
‘shared_pool_size‘,
‘pga_aggregate_target‘);
--2.查找前十条性能差的sql(磁盘读取较大，缺少索引或语句不合理)
SELECT *
FROM (SELECT PARSING_USER_ID EXECUTIONS,
SORTS,
COMMAND_TYPE,
DISK_READS,
sql_text
FROM v$sqlarea
ORDER BY disk_reads DESC)
WHERE ROWNUM < 10;
SELECT sql_text, hash_value, executions, buffer_gets, disk_reads, parse_calls
FROM V$SQLAREA
WHERE buffer_gets > 10000000 OR disk_reads > 1000000
ORDER BY buffer_gets + 100 * disk_reads DESC;
--3.根据unix上Top命令看到的PID,查找对应的SQl
SELECT P.pid pid,
S.sid sid,
P.spid spid,
S.username username,
S.osuser osname,
P.serial# S_#,
P.terminal,
P.program program,
P.background,
S.status,
RTRIM(SUBSTR(a.sql_text, 1, 80)) SQL
FROM v$process P, v$session S, v$sqlarea A
WHERE P.addr = s.paddr
AND S.sql_address = a.address(+)
AND P.spid LIKE ‘%CPU最高的进程对应的PID%‘;
--4.察看IO情况：
select
df.name 文件名,
fs.phyrds 读次数,
fs.phywrts 写次数,
(fs.readtim/decode(fs.phyrds,0,-1,fs.phyrds)) 读时间,
(fs.writetim/decode(fs.phywrts,0,-1,fs.phywrts)) 写时间
from v$datafile df,
v$filestat fs
where df.file#=fs.file#
order by df.name;
--5.表空间察看
SELECT UPPER(F.TABLESPACE_NAME) "表空间名",
D.TOT_GROOTTE_MB "表空间大小(M)",
D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空间(M)",
TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100, 2), ‘990.99‘) "使用比",
F.TOTAL_BYTES "空闲空间(M)",
F.MAX_BYTES "最大块(M)"
FROM (SELECT TABLESPACE_NAME,
ROUND(SUM(BYTES) / (1024 * 1024), 2) TOTAL_BYTES,
ROUND(MAX(BYTES) / (1024 * 1024), 2) MAX_BYTES
FROM SYS.DBA_FREE_SPACE GROUP BY TABLESPACE_NAME) F,
(SELECT DD.TABLESPACE_NAME,ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB FROM SYS.DBA_DATA_FILES DD
GROUP BY DD.TABLESPACE_NAME) D WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME
ORDER BY 4 DESC;
-- 数据表总行数排序
select t.table_name, t.num_rows, t.*
from user_tables t
where t.num_rows > 0
order by t.num_rows desc
-- 普通表数据大小排序
select segment_name, trunc(bytes/1024/1024)
from user_segments
where segment_type = ‘TABLE‘
order by bytes desc;
-- 含LOB类型表的数据大小
SELECT A.TABLE_NAME,
A.COLUMN_NAME,
trunc(B.BYTES / 1024 / 1024),
B.SEGMENT_NAME,
B.SEGMENT_TYPE,
B.TABLESPACE_NAME,
B.BLOCKS,
B.EXTENTS
FROM USER_LOBS A, USER_SEGMENTS B
WHERE A.SEGMENT_NAME = B.SEGMENT_NAME
ORDER BY B.BYTES DESC;
-- 数据表总的数据大小占用
select rowSize + nvl(lobSize, 0) dataSize, t1.*, t2.*
from (
select segment_name, trunc(bytes/1024/1024) rowSize
from user_segments
where segment_type = ‘TABLE‘
) t1 left join (
SELECT A.TABLE_NAME,
A.COLUMN_NAME,
trunc(B.BYTES / 1024 / 1024) lobSize,
B.SEGMENT_NAME,
B.SEGMENT_TYPE,
B.TABLESPACE_NAME,
B.BLOCKS,
B.EXTENTS
FROM USER_LOBS A, USER_SEGMENTS B
WHERE A.SEGMENT_NAME = B.SEGMENT_NAME
) t2 on t1.segment_name = t2.table_name
order by rowSize + nvl(lobSize, 0) desc
--6.运行时间很长的SQL
select username,
sid,
opname,
round(sofar * 100 / totalwork, 0) || ‘%‘ as progress,
time_remaining,
sql_text
from v$session_longops, v$sql
where time_remaining <> 0
and sql_address = address
and sql_hash_value = hash_value;
--7.锁相关的查询
select ‘kill -9 ‘||PS.SPID,
‘alter system kill session ‘‘‘||vs.sid||‘,‘||vs.serial#||‘‘‘;‘,
/* DECODE(V$LOCK.TYPE, ‘TM‘, ‘TABLE LOCK‘, ‘TX‘, ‘ROW LOCK‘, NULL) LOCK_LEVEL,*/
Decode(VL.LOCKED_MODE,0,‘[0] none‘,
1,‘[1] null 空‘,
2,‘[2] Row-S 行共用(RS)：共用表鎖，sub share ‘,
3,‘[3] Row-X 行獨佔(RX)：用於行的修改，sub exclusive ‘,
4,‘[4] Share 共用鎖(S)：阻止其他DML操作，share‘,
5,‘[5] S/Row-X 共用行獨佔(SRX)：阻止其他事務操作，share/sub exclusive ‘,
6,‘[6] exclusive 獨佔(X)：獨立訪問使用，exclusive ‘,
‘[‘||VL.LOCKED_MODE||‘] Other Lock‘) LockMode,
PS.SPID,OS_USER_NAME,VS.PROGRAM,VS.MACHINE,ORACLE_USERNAME,OBJECT_NAME,vs.LOGON_TIME ,
Vs.status,vs.MODULE
from V$LOCKED_OBJECT VL ,DBA_OBJECTS OB ,V$SESSION VS ,v$process PS
WHERE VL.OBJECT_ID = OB.OBJECT_ID
AND VL.SESSION_ID = VS.SID
AND Ps.ADDR = Vs.PADDR
select ‘kill -9 ‘||PS.SPID,
‘alter system kill session ‘‘‘||vs.sid||‘,‘||vs.serial#||‘‘‘;‘,
/* DECODE(V$LOCK.TYPE, ‘TM‘, ‘TABLE LOCK‘, ‘TX‘, ‘ROW LOCK‘, NULL) LOCK_LEVEL,*/
Decode(VL.LOCKED_MODE,0,‘[0] none‘,
1,‘[1] null 空‘,
2,‘[2] Row-S 行共用(RS)：共用表鎖，sub share ‘,
3,‘[3] Row-X 行獨佔(RX)：用於行的修改，sub exclusive ‘,
4,‘[4] Share 共用鎖(S)：阻止其他DML操作，share‘,
5,‘[5] S/Row-X 共用行獨佔(SRX)：阻止其他事務操作，share/sub exclusive ‘,
6,‘[6] exclusive 獨佔(X)：獨立訪問使用，exclusive ‘,
‘[‘||VL.LOCKED_MODE||‘] Other Lock‘) LockMode,
PS.SPID,OS_USER_NAME,VS.PROGRAM,VS.MACHINE,ORACLE_USERNAME,OBJECT_NAME,vs.LOGON_TIME ,
Vs.status,vs.MODULE, vs.SQL_ID, st.SQL_TEXT
from V$LOCKED_OBJECT VL ,DBA_OBJECTS OB ,V$SESSION VS ,v$process PS, v$sqlarea st
WHERE VL.OBJECT_ID = OB.OBJECT_ID
AND VL.SESSION_ID = VS.SID
AND Ps.ADDR = Vs.PADDR
and vs.SQL_ID = st.SQL_ID
AND VS.USERNAME = ‘LC019999‘
select st.SQL_FULLTEXT, vs.*
from v$session vs
join v$sql st on vs.SQL_ID = st.SQL_ID
where vs.USERNAME = ‘scott‘
and st.SQL_TEXT like ‘%%‘
--8.产生kill会话的Sql语句
select A.SID,
B.SPID,
A.SERIAL#,
a.lockwait,
A.USERNAME,
A.OSUSER,
a.logon_time,
a.last_call_et / 3600 LAST_HOUR,
A.STATUS,
‘orakill ‘ || sid || ‘ ‘ || spid HOST_COMMAND,
‘alter system kill session ‘‘‘ || A.sid || ‘,‘ || A.SERIAL# || ‘‘‘‘ SQL_COMMAND
from v$session A, V$PROCESS B
where A.PADDR = B.ADDR
AND SID > 6;
-- 最近10分钟最消耗CPU的SQL语句：
select sql_text
from (
select sql_id,count(*) as cn
from v$active_session_history
where sample_time > sysdate - 10/24/60
and session_type <> ‘BACKGROUND‘
and SESSION_STATE = ‘ON CPU‘
group by sql_id
order by cn desc
) ash, v$sql s
where ash.sql_id=s.sql_id;
-- 最近10分钟最消耗IO的SQL语句：
select sql_text
from (
select sql_id,count(*) as cn
from v$active_session_history
where sample_time > sysdate - 10/24/60
and session_type <> ‘BACKGROUND‘
and WAIT_CLASS=‘User I/O‘
group by sql_id
order by cn desc
) ash, v$sql s
where ash.sql_id=s.sql_id;
--清空缓存，Command window执行：
Alter system flush shared_pool;
--analyze table 更新统计信息：
analyze table my_table compute statistics;
--删除数据后，释放数据空间
alter table my_table enable row movement;
alter table my_table shrink space cascade;
alter table my_table disable row movement;
获取指定SQL在内存中的执行计划： select sql_id,child_number,sql_text from v$sql where sql_text like ‘select count(1) from emp a where a.dept_no =%‘; select * from table(DBMS_XPLAN.DISPLAY_CURSOR(‘sql_id‘,0)); 1、PL/SQL Developer 中使用F5 2、explain plan for select count(1) from emp a where a.dept_no=5; select * from table(dbms_xplan.display()); 3、sqlplus中使用 set autotrace traceonly exp;
Oracle常用的诊断语句
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本文系统来源：http://www.cnblogs.com/zhaoguan_wang/p/4584284.html
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