Examine the parameter for your database instance: You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan: Identify the reason why the optimizer chose different execution plans.（） [" The optimizer used a dynamic plan for the query."," The optimizer chose different plans because automatic dynamic sampling was enabled."," The optimizer used re-optimization cardinality feedback for the query."," The optimizer chose different plan because extended statistics were created for the columns used."]
低压封堵作业中，液动挡板在使用后要清洗，活塞杆和两根导向轴的表面及其它配合表面涂上（），保持清洁与润滑。 ["润滑脂","二硫化钼","黄甘油","黄油"]
我国古代不少统治者重视制度的创新，下列制度沿用时间最长的是（）。 ["科举制度","丁税制度","丞相制度","三省六部制"]
Which two statements are true about Shared SQL Area and Private SQL Area（） ["Shared SQL Area will be allocated in the shared pool.","Shared SQL Area will be allocated when a session starts.","Shared SQL Area will be allocated in the large pool always.","Private SQL Area will be allocated in the Program Global Area （PGA） always.","Shared SQL Area and Private SQL Area will be allocated in the PGA or large pool.","The number of Private SQL Area allocations is dependent on the OPEN_CURSORS parameter."]
Which two statements are correct about database transportation？（） [" The source and target platforms must be the same"," Redo logs，control files and temp files are also transported"," The transported database must have the same database identifier （DBID） as the source database and cannot be changed"," The COMPATIBLE parameter must be set to 10.0.0.0 or higher and the database must be opened in readonly mode before being transported"," Recovery Manager （RMAN） is used to convert the necessary data files of the database if the target platform is different and has different endian format"]
什么是无损检测？
