控制smon是否回滚事务

关闭smon清理：
SQL> oradebug setorapid
SQL> oradebug event 10513 trace name context forever, level 2


打开smon清理：
SQL> oradebug setorapid
SQL> oradebug event 10513 trace name context off

这么查：
select pid, program from v$process where program like '%SMON%';

但是这个10513的 event 含义代表什么可以看 $ORACLE_HOME/rdbms/mesg/oraus.msg



参考：
How to Disable Parallel Transaction Recovery When Parallel Txn Recovery is Active (Doc ID 238507.1)


方便版：

取消并行回滚，因为并行进程互相干扰，有时并行不如串行回滚效率高，常用于对索引的并行更新回滚。

找到smon的pid信息
col program for a40
select pid, program from v$process where program like '%SMON%';

根据pid设置事件
oradebug setorapid '&smon_pid';
oradebug event 10513 trace name context forever, level 2

杀掉并行进程
select 'kill -9 '||SPID c from V$PROCESS where PID in (select PID from V$FAST_START_SERVERS);

取消并行回滚
alter system set fast_start_parallel_rollback=false;

继续回滚
oradebug setorapid '&smon_pid';
oradebug event 10513 trace name context off

查看回滚段大小（建议每2分钟执行一次，然后比较）

set lines 120
col useg format a30
alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';
select c.*,round(c.undoblocks*(select value from v$parameter where name='db_block_size')/1024/1024,1)MB
from (
select sysdate,b.name useg, b.inst# instid, b.status$ status, a.ktuxeusn
xid_usn, a.ktuxeslt xid_slot, a.ktuxesqn xid_seq, a.ktuxesiz undoblocks
from x$ktuxe a, undo$ b
where a.ktuxesta = 'ACTIVE' and a.ktuxecfl like '%DEAD%'
and a.ktuxeusn = b.us#) c;