客户数据库版本10.2.0.4，启动成功之后立马crash，让我们协助解决

Thu Jul  4 13:03:10 2019
Completed: ALTER DATABASE OPEN
Thu Jul  4 13:03:10 2019
db_recovery_file_dest_size of 2048 MB is 0.00% used. This is a
user-specified limit on the amount of space that will be used by this
database for recovery-related files, and does not reflect the amount of
space available in the underlying filesystem or ASM diskgroup.
Thu Jul  4 13:04:01 2019
Errors in file /oracle/app/oracle/admin/orcl/bdump/orcl_reco_22268.trc:
ORA-00600: internal error code, arguments: [2252], [3987], [3375047096], [], [], [], [], []
Thu Jul  4 13:04:01 2019
Errors in file /oracle/app/oracle/admin/orcl/bdump/orcl_reco_22268.trc:
ORA-00600: internal error code, arguments: [2252], [3987], [3375047096], [], [], [], [], []
Thu Jul  4 13:04:02 2019
Errors in file /oracle/app/oracle/admin/orcl/bdump/orcl_reco_22268.trc:
ORA-00600: internal error code, arguments: [2252], [3987], [3375047096], [], [], [], [], []
Thu Jul  4 13:04:02 2019
RECO: terminating instance due to error 476
Instance terminated by RECO, pid = 22268

根据以往经验记录一次ORA-00600[2252]故障解决,很可能是scn过大引起.通过Oracle数据库异常恢复检查脚本(Oracle Database Recovery Check)检查scn相关信息

从ORA-600 2252错误信息看,由于scn可能超过该数据库的天花板理论上而导致该问题,而reco进程主要是由于分布式事务引起,通过和客户确认,该库有通过dblink去访问11204版本oracle,而从2019年6月23日之后scn的算法发生了一些改变(SCN Compatibility问题汇总-2019年6月23日),导致数据库可以支持更大的scn,从而当低版本需要进行分布式事务操作之时,可能导致数据库异常.

处理方案：通过临时屏蔽分布式事务,让数据库临时正常工作;长期解决方案需要把数据库版本升级,避免scn引起相关问题