今天有台数据库一个小时之内连续宕机两次，相同的错误，都是ORA-600 17147 导致内存crash后PMON杀死实例

ORA-00600: internal error code, arguments: [17147], [0xFB0AC7920], [], [], [], [], [], [], [], [], [], []

ORA-1092 : opiodr aborting process unknown ospid (19839_47665993829568)

Wed Jul 11 20:58:25 2012

ORA-1092 : opitsk aborting process

Wed Jul 11 20:58:25 2012

ORA-1092 : opiodr aborting process unknown ospid (19837_47822817557696)

Wed Jul 11 20:58:25 2012

ORA-1092 : opitsk aborting process

Instance terminated by PMON, pid = 3245

通过core_dump里面有一条特别长dynamic_sampling的SQL,in里面有36000+的or，后来一查对应于bug 8277300

通过设置optimizer_dynamic_sampling=1降低动态搜集的等级，然后cron里面设置脚本定制化的收集信息

根据不同的optimizer_dynamic_sampling级别而不同，他总共有10个级别，分别如下：

· Level 0: Do not use dynamic sampling.

· Level 1: The number of blocks sampled is the default number of dynamic sampling blocks (32).

· Level 2: The number of blocks sampled is 2 times the default number of dynamic sampling blocks.

· Level 3: The number of blocks sampled is 4 times the default number of dynamic sampling blocks.

· Level 4: The number of blocks sampled is 8 times the default number of dynamic sampling blocks.

· Level 5: The number of blocks sampled is 16 times the default number of dynamic sampling blocks.

· Level 6: The number of blocks sampled is 32 times the default number of dynamic sampling blocks.

· Level 7: The number of blocks sampled is 64 times the default number of dynamic sampling blocks.

· Level 8: The number of blocks sampled is 128 times the default number of dynamic sampling blocks.

· Level 9: The number of blocks sampled is 256 times the default number of dynamic sampling blocks.

· Level 10: Read all blocks in the table.