在数据库open过程中常遇到ORA-01555汇总

在数据库open的过程中，select ctime, mtime, stime from obj$ where obj# = :1语句报ORA-01555错误,数据库无法正常open
一般情况下会报某个回滚段,但是这里ORA-01555: snapshot too old: rollback segment number 0 with name “SYSTEM” too small这里直接报了system(系统回滚段),属于少见情况

Fri Jun 26 11:47:31 2015
SMON: enabling cache recovery
Fri Jun 26 11:47:31 2015
ORA-01555 caused by SQL statement below (SQL ID: 4krwuz0ctqxdt, SCN: 0x0b41.37629378):
Fri Jun 26 11:47:31 2015
select ctime, mtime, stime from obj$ where obj# = :1
Fri Jun 26 11:47:31 2015
Errors in file /orabin/admin/doocrm/udump/doocrm_ora_5046722.trc:
ORA-00704: bootstrap process failure
ORA-00704: bootstrap process failure
ORA-00604: error occurred at recursive SQL level 1
ORA-01555: snapshot too old: rollback segment number 0 with name "SYSTEM" too small
Error 704 happened during db open, shutting down database
USER: terminating instance due to error 704
Instance terminated by USER, pid = 5046722
ORA-1092 signalled during: alter database open resetlogs...

在数据库open的过程中,select increment$,minvalue,maxvalue,cycle#,order$,cache,highwater,audit$,flags from seq$ where obj#=:1语句上报ORA-01555,导致数据库open失败

ARC0: Becoming the 'no SRL' ARCH
Sun Jun 28 16:08:22 2015
ARC1: Becoming the heartbeat ARCH
Sun Jun 28 16:08:22 2015
SMON: enabling cache recovery
Sun Jun 28 16:08:22 2015
ORA-01555 caused by SQL statement below (SQL ID: 7bd391hat42zk, Query Duration=0 sec, SCN: 0x0d27.0a1ce29d):
Sun Jun 28 16:08:22 2015
select /*+ rule */ name,file#,block#,status$,user#,undosqn,xactsqn,scnbas,scnwrp,DECODE(inst#,0,NULL,inst#),ts#,spare1 from undo$ where us#=:1
Sun Jun 28 16:08:22 2015
Errors in file /oracle/app/oracle/admin/ibsscrm/udump/xxxx_ora_30212428.trc:
ORA-00604: error occurred at recursive SQL level 1
ORA-01555: snapshot too old: rollback segment number 0 with name "SYSTEM" too small
Error 604 happened during db open, shutting down database
USER: terminating instance due to error 604
Instance terminated by USER, pid = 30212428
ORA-1092 signalled during: alter database open...

出现这类问题,一般是由于obj$,seq$,undo$等基表上对象scn大于数据库当前scn或者是由于这些表上有事务未提交,出现上述两种情况,数据库需要找对应的undo的回滚段中记录,而此时对应的回滚段异常(或者是由于redo未进行正常前滚,导致上述对象或者回滚段记录不正常),从而出现类似情况,一般出现此类情况,可以通过10046定位到block，然后故障原因采用bbed修改scn或者bbed提交事务来解决此类问题.