使用Oracle的外部表查询警告日志文件

使用Oracle的外部表查询警告日志文件

从Oracle9i开始，Oracle的外部表技术（Oracle External Tables）被极大的增强，通过外部表访问外部数据增强了Oracle数据库和外部数据源进行数据交互的能力，对于数据仓库和ETL来说，这些增强极大的方便了数据访问。

对于DBA来说，最常见一个例子是可以使用外部表来访问警告日志文件或其他跟踪文件.

以下一个例子用来说明外部表的用途。

首先需要创建一个Directory：

[oracle@jumper oracle]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Sun Oct 15 21:42:28 2006

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to:

Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production

With the Partitioning option

JServer Release 9.2.0.4.0 - Production

SQL> create or replace directory bdump

2 as '/opt/oracle/admin/eygle/bdump';

Directory created.

SQL> col DIRECTORY_PATH for a30

SQL> col owner for a10

SQL> select * from dba_directories;

OWNER DIRECTORY_NAME DIRECTORY_PATH

---------- ------------------------------ ------------------------------

SYS BDUMP /opt/oracle/admin/eygle/bdump

然后创建一个外部表:

SQL> create table alert_log ( text varchar2(400) )

2 organization external (

3 type oracle_loader

4 default directory BDUMP

5 access parameters (

6 records delimited by newline

7 nobadfile

8 nodiscardfile

9 nologfile

10 )

11 location('alert_eygle.log')

12 )

13 reject limit unlimited

14 /

Table created.

然后我们就可以通过外部表进行查询警告日志的内容:

SQL> select * from alert_log where rownum < 51;

TEXT

----------------------------------------------------------------------------------------- Mon Jun 26 12:00:24 2006

Starting ORACLE instance (normal)

Mon Jun 26 12:00:25 2006

WARNING: EINVAL creating segment of size 0x0000000008c00000 fix shm parameters in /etc/system or equivalent

LICENSE_MAX_SESSION = 0

LICENSE_SESSIONS_WARNING = 0

SCN scheme 2

Using log_archive_dest parameter default value

LICENSE_MAX_USERS = 0

SYS auditing is disabled

Starting up ORACLE RDBMS Version: 9.2.0.4.0.

System parameters with non-default values:

processes = 150

timed_statistics = TRUE

shared_pool_size = 104857600

large_pool_size = 0

java_pool_size = 0

control_files = /opt/oracle/oradata/eygle/control01.ctl

db_block_size = 8192

db_cache_size = 16777216

db_cache_advice = ON

compatible = 9.2.0.0.0

db_file_multiblock_read_count= 16

fast_start_mttr_target = 300

log_checkpoints_to_alert = TRUE

undo_management = AUTO

undo_tablespace = UNDOTBS1

undo_retention = 10800

remote_login_passwordfile= EXCLUSIVE

db_domain =

instance_name = eygle

job_queue_processes = 10