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ORACLE 死锁分析过程

ORACLE 死锁分析
关于死锁一般3种处理方式
1、事前预测
2、资源分级
3、事后检测释放

我知道的ORACLE MYSQL都是采用第三种在行锁级别上的话。
这里分析一个ORACLE死锁,首先一个死锁肯定会生成一个TRACE文件,这里会记录很多信息如:
Deadlock graph:
                       ———Blocker(s)——–  ———Waiter(s)———
Resource Name          process session holds waits  process session holds waits
TX-0058000f-0000b473       649    1204     X            651    1252           X
TX-0019001c-0004e0b0       651    1252     X            649    1204           X

这里给出了进程和会话id
Rows waited on:
  Session 1204: obj – rowid = 0003D942 – AAA9lCAAEAADgaNAAI
  (dictionary objn – 252226, file – 4, block – 919181, slot – 8)
  Session 1252: obj – rowid = 0003D942 – AAA9lCAAEAADgaNAAa
  (dictionary objn – 252226, file – 4, block – 919181, slot – 26)
这里给出导致死锁的行

同时给出了最后触发死锁会话 1252的语句
—– Information for the OTHER waiting sessions —–
Session 1252:
  sid: 1252 ser: 35883 audsid: 7170593 user: 235/FEECORESV
    flags: (0x100045) USR/- flags_idl: (0x1) BSY/-/-/-/-/-
    flags2: (0x40009) -/-/INC
  pid: 651 O/S info: user: oracle, term: UNKNOWN, ospid: 13035
    image: oracle@oratest11
  client details:
    O/S info: user: sky, term: unknown, ospid: 1234
    machine: autobots program: JDBC Thin Client
    application name: JDBC Thin Client, hash value=2546894660
  current SQL:
  UPDATE *******
 
—– End of information for the OTHER waiting sessions —–
 
Information for THIS session:
 
—– Current SQL Statement for this session (sql_id=3vh5sc7pgtrjy) —–
UPDATE *******

那么到这里我们大概能够分析出
A:1204拿到AAA9lCAAEAADgaNAAa 行锁    B:1252 拿到 AAA9lCAAEAADgaNAAI 行锁
C:1204需要AAA9lCAAEAADgaNAAI 则等待   D:1252 需要  AAA9lCAAEAADgaNAAa 则触发死锁1204回滚

那么随后trace给出1204 C这一步等待时间和事物信息
SO: 0xee1fcd10, type: 4, owner: 0xf031e750, flag: INIT/-/-/0x00 if: 0x3 c: 0x3
     proc=0xf031e750, name=session, file=ksu.h LINE:12624, pg=0
    (session) sid: 1204 ser: 2443 trans: 0xe9221180, creator: 0xf031e750
              flags: (0x100045) USR/- flags_idl: (0x1) BSY/-/-/-/-/-
              flags2: (0x40009) -/-/INC
              DID: , short-term DID: 
              txn branch: (nil)
              oct: 6, prv: 0, sql: 0xf25d2278, psql: 0xc4346788, user: 235/FEECORESV
    ksuxds FALSE at location: 0
    service name: SYS$USERS
Current Wait Stack:
     0: waiting for ‘enq: TX – row lock contention’
        name|mode=0x54580006, usn<<16 | slot=0x19001c, sequence=0x4e0b0
        wait_id=33 seq_num=34 snap_id=1
        wait times: snap=3.001739 sec, exc=3.001739 sec, total=3.001739 sec
        wait times: max=infinite, heur=3.001739 sec
        wait counts: calls=1 os=1
        in_wait=1 iflags=0x15a0
随后给出了导致他等待会话的等待信息,这里不给出。当然随后还有很多类容,但是关键就是如上
但是这里并没有一个显示的事物执行的过程,如果要看到完整的语句我们需要日志挖掘,我挖掘出来的如下:

1204:
set transaction read write;
select * from TEST.TEST where ROWID = ‘AAA9lCAAEAADgaNAAa’ for update;
commit;
1252:
set transaction read write;
select * from TEST.TEST where ROWID = ‘AAA9lCAAEAADgaNAAI’ for update;
update TEST.TEST set “STATUS” = ‘SUCCESS’, “DETAIL” = ‘执行成功’, “RAW_UPDATE_TIME” = TO_TIMESTAMP(’19-SEP-16 01.27.25.714715 PM’) where “IDENTITY” = ‘39319’ and “STATUS” = ‘PROCESSING’ and “DETAIL” IS NULL and “RAW_UPDATE_TIME” = TO_TIMESTAMP(’19-SEP-16 01.27.24.611036 PM’) and ROWID = ‘AAA9lCAAEAADgaNAAa’;
commit;

这样能够清楚的看到1204的update并没有执行,而由于触发了deadlock回滚掉了。

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/7728585/viewspace-2125156/,如需转载,请注明出处,否则将追究法律责任。

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