如果在show alert -tail之后，遇到以下错误。

adrci> show alert -tail
DIA-48449: Tail alert can only apply to single ADR home

则需要先set home，比如：
adrci> show home
ADR Homes:
diag\clients\user_kenneth_zhang\host_366275074_11
diag\clients\user_system\host_366275074_11
diag\rdbms\orcl11g\orcl11g
diag\tnslsnr\prcsgil00066\listener
adrci> set home diag\rdbms\orcl11g\orcl11g
adrci> show alert -tail
2008-12-12 14:44:33.456000 +08:00
Starting background process SMCO
FBDA started with pid=7, OS id=4212
SMCO started with pid=18, OS id=3084
2008-12-12 14:44:34.628000 +08:00
replication_dependency_tracking turned off (no async multimaster replication fou
nd)
2008-12-12 14:44:37.425000 +08:00

如果在show alert -tail之后，遇到以下错误。

adrci> show alert -tail
DIA-48449: Tail alert can only apply to single ADR home

则需要先set home，比如：  
adrci> show home
ADR Homes:
diag\clients\user_kenneth_zhang\host_366275074_11
diag\clients\user_system\host_366275074_11
diag\rdbms\orcl11g\orcl11g
diag\tnslsnr\prcsgil00066\listener

adrci> set home diag\rdbms\orcl11g\orcl11g

adrci> show alert -tail
2008-12-12 14:44:33.456000 +08:00
Starting background process SMCO
FBDA started with pid=7, OS id=4212
SMCO started with pid=18, OS id=3084
2008-12-12 14:44:34.628000 +08:00
replication_dependency_tracking turned off (no async multimaster replication fou
nd)
2008-12-12 14:44:37.425000 +08:00
Starting background process QMNC
QMNC started with pid=20, OS id=3412
2008-12-12 14:44:55.974000 +08:00
db_recovery_file_dest_size of 4096 MB is 3.91% 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.
2008-12-12 14:45:28.882000 +08:00
Completed: ALTER DATABASE OPEN 
adrci>

Starting background process QMNC
QMNC started with pid=20, OS id=3412
2008-12-12 14:44:55.974000 +08:00
db_recovery_file_dest_size of 4096 MB is 3.91% 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.
2008-12-12 14:45:28.882000 +08:00
Completed: ALTER DATABASE OPEN
adrci>