188. You receive complaints from users regarding the high waiting time for their transactions. On
investigation, you find that some users are not committing their transactions though they are not
performing any activity for a long time. As a result, SQL statements need to wait for row-level locks.
Which two actions could you take to prevent this locking problem in the future? (Choose two.)
A.Decrease the IDLE_TIME resource limit in the profile assigned to the blocking users.
B.Use Database Resource Manager to automatically log out sessions that block others and are idle.
C.Set the limit in the profile of blocking users to control the number of blocks to be accessed in a session.
D.Decrease the maximum number of interested transaction list (ITL) slots for the segments on which the
blocking user performs the transaction.
Answer: AB
答案解析：
参考：http://blog.csdn.net/rlhua/article/details/13092965
题意：收到用户投诉说在事务期间经常要等待很长时间，经调查发现，有些用户不提交他们的事务且很长一段时间没有进行任何活动。结果，就会造成SQL语句行级锁，而其他人只能等待，怎样防止这种锁定问题？
A,对于阻塞用户减少 IDLE_TIME的资源限制，正确。通过数据库资源管理器提供的空闲时间限制，来指定哪些阻塞用户的会话的空间时间，超过该时间后将终止会话。
B,使用数据库资源管理器自动退出阻塞别人或者用户闲置的会话。正确。
C,设置阻塞用户的档案，以控制在一个会话中被访问的块的数量的限制。如此一来，被阻塞的用户如果想再次访问的时候就不能访问了。错误。
D,减少感兴趣的事务列表（ITL）插槽，用于阻止用户执行交易分类的最大数目。和C类似，如果此时空闲的用户想访问以前不感兴趣的事务，那么旧不能访问了。