You are maintaining your OLTP database in Oracle10g. While observing the performance of the database， you find that the log switch occurs more than once for every 20 minutes， affecting the database performance. Which factor is responsible for frequent log switches？（） ["the value of the UNDO_RETENTION initialization parameter","the value of the optimal redo log file size provided by the Redo Logfile Size Advisor","the online redo log files size","the number of redo log members in a grou"]
非遗传型变异
An administrator wants to test the performance of an application at different memory sizes. What is the most effective way to perform the test and collect statistical information for each test？（） ["Run DLPAR to change the LPAR memory for each test.","Run rmss command to simulate different memory for each test.","Run chdev command to limit the system memory size for each test.","Run chattr command to limit the system memory size for each test."]
保留金是发包人从承包人完成的合同工程款额中扣留的用于承包人完成工程缺陷和尾工义务的担保。
【背景资料】郑州市某小区6号楼工程由某某建筑集团第一分公司承建。2008年11月20日主体结构及砌体全部施工完毕。至2008年11月粉刷施工队开始进场施工，到2009年5月25日大面积粉刷结束，在2009年4月份大检查时发现个别房间粉刷层空鼓但无裂缝，开始组织少量人员进行维修，到2009年5月20日再次大检查时发现大部分房间粉刷层空鼓并且墙面有很多裂纹，这时引起公司重视，开始组织专家到现场查勘并查找墙面粉刷层空鼓、裂缝的原因。
请根据背景资料完成以下选项。施工管理把控不严是此次墙面粉刷层出现空鼓、裂缝的主要原因。
教师学习特点。
