教你怎样用Oracle方便地查看报警日志错误

在网上查了几天的资料，尝试综合清除告警日志内容及建外部表的方式来解决这一问题。

一：备份并清除告警日志内容

将每天的告警日志备份好，然后进行清除。

1:备份报警日志

在$oracle_home/sid/bdump/   目录下，
按日期备份alert_oracle_你的实例名.log这个文件,如：alert_oracle_orcl_201408111639_bak.log。

2:清除日志内容

打开报警日志文件，用true > 文件名 可清除掉里面的内容

具体示例：
假如，我现在第一次进行该设置，我先把现有的告警日志进行备份，如：

--备份文件名称：今天16点24分前的告警日志信息

[oracle@rac2 bdump]$ cp alert_orcl2.log alert_orcl2_before_201408111624_bak.log

-清空报警日志

[oracle@rac2 bdump]$ true > alert_orcl2.log

现在告警日志是空的。
切换下归档日志，检查报警日志里是否出现了新内容：

sql> alter system switch logfile;
system altered.

则现在alert_orcl2.log记录的是2014年8月11日16点24分后至你下次对报警日志进行备份，截取前的信息。

二：建外部表查看报警日志错误

 如果已建立了一个用户,并赋相应的权限，所以直接建立目录对象并建立外部表就可以了。

1．建立目录对象

sql> conn test / 123
connected.
sql> create directory bdump as '/oracle/u01/app/oracle/admin/db2/bdump';
directory created.

2．建立外部表

sql> create table alert_log(
text varchar2(400)
)organization external
(type oracle_loader
default directory bdump
access parameters
(records delimited by newline
)location('alert_db2.log')
);

3．测试首先查看能否查到alert_db2.log的内容

sql> select * from alert_log where rownum < 10;
text
--------------------------------------------------------------------------------
thu jun 11 00:51:46 2009
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/:/a
de/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
9 rows selected.

测试成功
然后我们测试查报警信息'ora-%'

sql> select * from alert_log where text like 'ora-%';
text
--------------------------------------------------------------------------------
ora-00202: control file: '/oracle/u01/app/oracle/product/10.2.0/db2/dbs/cntrldb2
.dbf'
ora-27037: unable to obtain file status
ora-205 signalled during: alter database  mount...
ora-00301: error in adding log file '/home/oracle/oracle/oradata/testdb/redo01.l
og' - file cannot be created
ora-27040: file create error
ora-1501 signalled during: create database db2
ora-00200: control file could not be created
text
--------------------------------------------------------------------------------
ora-00202: control file: '/oracle/u01/app/oracle/product/10.2.0/db2/dbs/cntrldb2
.dbf'
ora-27038: created file already exists
ora-1501 signalled during: create database db2
ora-00200: control file could not be created
ora-00202: control file: '/oracle/u01/app/oracle/product/10.2.0/db2/dbs/cntrldb2
.dbf'
ora-27038: created file already exists
ora-1501 signalled during: create database db2

 --假如，你的报警日志文件只包含今天的信息（可以通过备份并清除告警日志内容实现），则通过外部表可以查到当天产生了哪些错误。