问题背景：
客户dataguard宕机重启后，MRP进程因缺少数据文件起不来，
报错如下ORA-01111: name for data file 19 is unknown - rename to correct file
问题解决
1> 检查dataguard，sid已经正常启动，尝试启动MRP进程起不来，查看alert日志 （10g）
Errors in file /home/oracle/admin/oradb/bdump/zjport_mrp0_17798.trc:
ORA-01111: name for data file 19 is unknown - rename to correct file
ORA-01110: data file 19: '/home/oracle/product/10.2.0/db_1/dbs/UNNAMED00019'
ORA-01157: cannot identify/lock data file 19 - see DBWR trace file
ORA-01111: name for data file 19 is unknown - rename to correct file
ORA-01110: data file 19: '/home/oracle/product/10.2.0/db_1/dbs/UNNAMED00019'
MRP0: Background Media Recovery process shutdown (oradb)
查看alert日志发现datafile为19的数据库文件缺失，尝试重新创建
ALTER SYSTEM SET standby_file_management='MANUAL' SCOPE=BOTH;
alter database create datafile '/home/oracle/product/10.2.0/db_1/dbs/UNNAMED00019' as '/u01/oracle/oradata/oradb/test02.dbf'
ALTER SYSTEM SET standby_file_management='AUTO' SCOPE=BOTH;
重启MRP进程
ALTER DATABASE RECOVER managed standby database disconnect from session parallel 12;
2> 如果是11g，报错可能如下
File #1103 added to control file as 'UNNAMED01103' because
the parameter STANDBY_FILE_MANAGEMENT is set to MANUAL
The file should be manually created to continue.
Errors with log /oradb/db_dg_arc/oradb/oradb_2_193066_899639967.arc
MRP0: Background Media Recovery terminated with error 1274
Errors in file /u01/oracle/diag/rdbms/oradb/oradb/trace/oradb_pr00_25640.trc:
ORA-01274: cannot add datafile '+oradb/oradb/datafile/sysaux_04.dbf' - file could not be created
Managed Standby Recovery not using Real Time Apply
Recovery interrupted!
发现datafile为1103的数据文件确实，尝试重新创建
ALTER SYSTEM SET standby_file_management='MANUAL' SCOPE=BOTH;
alter database create datafile '/u01/oracle/product/db11gr2/dbs/UNNAMED01103' as '/sxbddj/sxbddjdat_u01/sxbddj/sysaux_04.dbf';
ALTER SYSTEM SET standby_file_management='AUTO' SCOPE=BOTH;
ALTER DATABASE RECOVER managed standby database disconnect from session parallel 12 ;
3> 如果不知道文件编号所代表的数据文件是哪一个，可以从主库中获取
SQL> select name from v$datafile where file#=1103;
NAME
--------------------------------------------------------------------------------
oradb/oradb/datafile/sysaux_04.dbf