由于生產(chǎn)的tomcat 經(jīng)常有假死問(wèn)題，困擾很久，最后發(fā)現(xiàn)有死鎖，解決辦法分享

1、查看死鎖

1)用dba用戶執(zhí)行以下語(yǔ)句select username,lockwait,status,machine,program from v$session where sid in

(select session_id from v$locked_object)

如果有輸出的結(jié)果，則說(shuō)明有死鎖，且能看到死鎖的機(jī)器是哪一臺(tái)。字段說(shuō)明：

Username：死鎖語(yǔ)句所用的數(shù)據(jù)庫(kù)用戶；

Lockwait：死鎖的狀態(tài)，如果有內(nèi)容表示被死鎖。

Status： 狀態(tài)，active表示被死鎖

Machine： 死鎖語(yǔ)句所在的機(jī)器。

Program： 產(chǎn)生死鎖的語(yǔ)句主要來(lái)自哪個(gè)應(yīng)用程序

2)用dba用戶執(zhí)行以下語(yǔ)句，可以查看到被死鎖的語(yǔ)句。select sql_text from v$sql where hash_value in

(select sql_hash_value from v$session where sid in

(select session_id from v$locked_object))

2、死鎖的解決方法

1)查找死鎖的進(jìn)程：SELECT s.username,l.OBJECT_ID,l.SESSION_ID,s.SERIAL#,

l.ORACLE_USERNAME,l.OS_USER_NAME,l.PROCESS

FROM V$LOCKED_OBJECT l,V$SESSION S WHERE l.SESSION_ID=S.SID;

2)kill掉這個(gè)死鎖的進(jìn)程：alter system kill session ‘sid,serial#’; (其中sid=l.session_id)

3)如果還不能解決：select pro.spid from v$session ses,

v$process pro

where

ses.sid=XX

and ses.paddr=pro.addr;

其中sid用死鎖的sid替換:

--ORACLE 就是查表，需要SYSTEM，SYS(有相應(yīng)權(quán)限的用戶)執(zhí)行下面的SQL語(yǔ)句就可以了查看鎖代碼SELECT sn.username,

m.SID,

sn.SERIAL#,

m.TYPE,

DECODE(m.lmode,

0,

'None',

1,

'Null',

2,

'Row Share',

3,

'Row Excl.',

4,

'Share',

5,

'S/Row Excl.',

6,

'Exclusive',

lmode,

LTRIM(TO_CHAR(lmode, '990'))) lmode,

DECODE(m.request,

0,

'None',

1,

'Null',

2,

'Row Share',

3,

'Row Excl.',

4,

'Share',

5,

'S/Row Excl.',

6,

'Exclusive',

request,

LTRIM(TO_CHAR(m.request, '990'))) request,

m.id1,

m.id2

FROM v$session sn, v$lock m

WHERE (sn.SID = m.SID AND m.request != 0) --存在鎖請(qǐng)求，即被阻塞

OR (sn.SID = m.SID --不存在鎖請(qǐng)求，但是鎖定的對(duì)象被其他會(huì)話請(qǐng)求鎖定

AND m.request = 0 AND lmode != 4 AND

(id1, id2) IN (SELECT s.id1, s.id2

FROM v$lock s

WHERE request != 0

AND s.id1 = m.id1

AND s.id2 = m.id2))

ORDER BY id1, id2, m.request;

--解鎖代碼alter system kill session 'sid,SERIAL#';

--查看死鎖信息SELECT bs.username "Blocking User", bs.username "DB User",

ws.username "Waiting User", bs.SID "SID", ws.SID "WSID",

bs.serial# "Serial#", bs.sql_address "address",

bs.sql_hash_value "Sql hash", bs.program "Blocking App",

ws.program "Waiting App", bs.machine "Blocking Machine",

ws.machine "Waiting Machine", bs.osuser "Blocking OS User",

ws.osuser "Waiting OS User", bs.serial# "Serial#",

ws.serial# "WSerial#",

DECODE (wk.TYPE,

'MR', 'Media Recovery',

'RT', 'Redo Thread',

'UN', 'USER Name',

'TX', 'Transaction',

'TM', 'DML',

'UL', 'PL/SQL USER LOCK',

'DX', 'Distributed Xaction',

'CF', 'Control FILE',

'IS', 'Instance State',

'FS', 'FILE SET',

'IR', 'Instance Recovery',

'ST', 'Disk SPACE Transaction',

'TS', 'Temp Segment',

'IV', 'Library Cache Invalidation',

'LS', 'LOG START OR Switch',

'RW', 'ROW Wait',

'SQ', 'Sequence Number',

'TE', 'Extend TABLE',

'TT', 'Temp TABLE',

wk.TYPE

) lock_type,

DECODE (hk.lmode,

0, 'None',

1, 'NULL',

2, 'ROW-S (SS)',

3, 'ROW-X (SX)',

4, 'SHARE',

5, 'S/ROW-X (SSX)',

6, 'EXCLUSIVE',

TO_CHAR (hk.lmode)

) mode_held,

DECODE (wk.request,

0, 'None',

1, 'NULL',

2, 'ROW-S (SS)',

3, 'ROW-X (SX)',

4, 'SHARE',

5, 'S/ROW-X (SSX)',

6, 'EXCLUSIVE',

TO_CHAR (wk.request)

) mode_requested,

TO_CHAR (hk.id1) lock_id1, TO_CHAR (hk.id2) lock_id2,

DECODE

(hk.BLOCK,

0, 'NOT Blocking', /**//* Not blocking any other processes */

1, 'Blocking', /**//* This lock blocks other processes */

2, 'Global', /**//* This lock is global, so we can't tell */

TO_CHAR (hk.BLOCK)

) blocking_others

FROM v$lock hk, v$session bs, v$lock wk, v$session ws

WHERE hk.BLOCK = 1

AND hk.lmode != 0

AND hk.lmode != 1

AND wk.request != 0

AND wk.TYPE(+) = hk.TYPE

AND wk.id1(+) = hk.id1

AND wk.id2(+) = hk.id2

AND hk.SID = bs.SID(+)

AND wk.SID = ws.SID(+)

AND (bs.username IS NOT NULL)

AND (bs.username <> 'SYSTEM')

AND (bs.username <> 'SYS')

ORDER BY 1;

由最代碼官方編輯于2013-12-13 22:58:42

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