如何查看数据库alert日志文件

1、查看操作系统版本
SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE 10.2.0.1.0 Production
TNS for Linux: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
SQL>

2、查看预警日志文件（alert_sid.log）的位置
SQL> show parameter dump
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
background_core_dump string partial
background_dump_dest string /u01/oracle/admin/bdump
core_dump_dest string /u01/oracle/admin/cdump
max_dump_file_size string 10240
shadow_core_dump string partial
user_dump_dest string /u01/oracle/admin/udump

3、创建目录alert
注意：directory不是实体，只是一个指向，指向os中一个路径
SQL> create or replace directory alert as '/u01/oracle/admin/bdump';
Directory created.
SQL>

4、创建外部表alert
SQL> create table alert
1 (log varchar2(1000))
2 organization external
3 (type oracle_loader
4 default directory alert
5 access parameters
6 (records delimited by newline)
7 location ('alert_PROD.log'))
8 reject limit unlimited;
Table created.

5、查看alert中的内容
SQL> select * from alert where rownum<20;
LOG
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Wed Feb 27 11:05:11 2013
Starting ORACLE instance (normal)
Cannot determine all dependent dynamic libraries for /proc/self/exe
Unable to find dynamic library libocr10.so in search paths
RPATH = /ade/aime1_build2101/oracle/has/lib/:/ade/aime1_build2101/oracle/lib/:/ade/aime1_build2101/oracle/has/lib/:
LD_LIBRARY_PATH is not set!
The default library directories are /lib and /usr/lib
Unable to find dynamic library libocrb10.so in search paths
Unable to find dynamic library libocrutl10.so in search paths
Unable to find dynamic library libocrutl10.so in search paths
LICENSE_MAX_SESSION = 0
LICENSE_SESSIONS_WARNING = 0
Picked latch-free SCN scheme 2
Using LOG_ARCHIVE_DEST_1 parameter default value as /u01/oracle/product/10.2.0/db_1/dbs/arch
Autotune of undo retention is turned on.
IMODE=BR
ILAT =10
LICENSE_MAX_USERS = 0
SYS auditing is disabled
19 rows selected.
SQL>

6、看看数据库有哪些 可爱的ORA- 错误吧
SQL> select * from alert where log like '%ORA-%';
LOG
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ORA-959 signalled during: alter database default tablespace users...
ORA-959 signalled during: drop tablespace uses...
ORA-12919 signalled during: drop tablespace users...
ORA-1549 signalled during: drop tablespace users...
ORA-1505 signalled during: alter database add logfile group 1
ORA-1184 signalled during: alter database add logfile group 1
ORA-1013 signalled during: alter tablespace tts read only...
ORA-1013 signalled during: alter tablespace tts read only...
ORA-1013 signalled during: alter tablespace users read only...
ORA-1539 signalled during: alter tablespace users read only...

详细出处参考：http://www.jb51.net/article/34590.htm