数据库hang住了，如何收集日志并分析

数据库如果出了性能问题，非常慢，请按以下方式收集现场信息：
例：
SQL>sqlplus "/ as sysdba"
如果不行，用 sqlplus -prelim / as sysdba
SQL> oradebug setmypid
Statement processed.
SQL> oradebug unlimit;
Statement processed.
SQL> oradebug -g all hanganalyze 3
Hang Analysis in /u01/app/oracle/diag/rdbms/luo/luo/trace/luo_ora_10495.trc
等一两分钟后再执行
SQL> oradebug -g all  hanganalyze 3
Hang Analysis in /u01/app/oracle/diag/rdbms/luo/luo/trace/luo_ora_10495.trc
SQL>oradebug -g all dump systemstate 266
SQL> oradebug tracefile_name
/u01/app/oracle/diag/rdbms/luo/luo/trace/luo_ora_10495.trc
create table temp_sql1 as select * from  v$sqlarea;
create table temp_sessionhis1 as  select * from v$active_session_history;
create table temp_bh as select * from X$BH;
create table temp_sessionwait as select * from v$session_wait;
create table temp_latchchildren as select * from v$latch_children;
create table temp_latch as select * from v$latch;
create table temp_lock as select * from gv$lock;