Oracle 10.2数据库管理员指南-27章

27使用调度程序

Oracle Database provides database job capabilities through Oracle Scheduler (the Scheduler). This chapter explains how to use the various Scheduler components, and discusses the following topics:

调度程序对象和它们的命名

使用Jobs

使用Programs

使用Schedules

使用Job Classes

使用Windows

使用Window Groups

使用Events

使用Chains

分配资源通过jobs

Note:

This chapter describes how to use the DBMS_SCHEDULER package to work with Scheduler components. You can accomplish the same tasks using Oracle Enterprise Manager.

使用jobs

一个job是一个调度和一个程序的结合，还有额外的被程序要求的参数。这一部分给你介绍了基本的job任务和讨论下列主题：

Job任务和他们的存储过程

创建jobs

复制jobs

修改jobs

运行jobs

停止jobs

仍掉jobs

关闭jobs

开启jobs

Creating Jobs Using a Named Program

You can also create a job by pointing to a named program instead of inlining its action. To create a job using a named program, you specify the value for program_name in the CREATE_JOB procedure when creating the job and do not specify the values for job_type, job_action, and number_of_arguments.

To use an existing program when creating a job, the owner of the job must be the owner of the program or have EXECUTE privileges on it. An example of using the CREATE_JOB procedure with a named program is the following statement, which creates a job called my_new_job1:

BEGIN

DBMS_SCHEDULER.CREATE_JOB (

   job_name          =>  'my_new_job1',

   program_name      =>  'my_saved_program',

   repeat_interval   =>  'FREQ=DAILY;BYHOUR=12',

   comments          =>  'Daily at noon');

END;

Creating Jobs Using a Named Schedule

You can also create a job by pointing to a named schedule instead of inlining its schedule. To create a job using a named schedule, you specify the value for schedule_name in the CREATE_JOB procedure when creating the job and do not specify the values for start_date, repeat_interval, and end_date.

You can use any named schedule to create a job because all schedules are created with access to PUBLIC. An example of using the CREATE_JOB procedure with a named schedule is the following statement, which creates a job called my_new_job2:

BEGIN

DBMS_SCHEDULER.CREATE_JOB (

   job_name                 =>  'my_new_job2',

   job_type                 =>  'PLSQL_BLOCK',

   job_action               =>  'BEGIN SALES_PKG.UPDATE_SALES_SUMMARY; END;',

   schedule_name            =>  'my_saved_schedule');

END;

Creating Jobs Using a Named Program and Schedule

A job can also be created by pointing to both a named program and schedule. An example of using the CREATE_JOB procedure with a named program and schedule is the following statement, which creates a new job called my_new_job3 based on the existing program my_saved_program1 and the existing schedule my_saved_schedule1:

BEGIN

DBMS_SCHEDULER.CREATE_JOB (

   job_name            =>  'my_new_job3',

   program_name        =>  'my_saved_program1',

   schedule_name       =>  'my_saved_schedule1');

END;

Copying Jobs

You copy a job using the COPY_JOB procedure or Enterprise Manager. This call copies all the attributes of the old job to the new job except the new job is created disabled and has another name.

See Oracle Database PL/SQL Packages and Types Reference for detailed information about the COPY_JOB procedure.

Altering Jobs

You alter a job using the SET_ATTRIBUTE procedure or Enterprise Manager. All jobs can be altered, and, with the exception of the job name, all job attributes can be changed. If there is a running instance of the job when the SET_ATTRIBUTE call is made, it is not affected by the call. The change is only seen in future runs of the job.

In general, you should not alter a job that was automatically created for you by the database. Jobs that were created by the database have the column SYSTEM set to TRUE in job views. The attributes of a job are available in the *_SCHEDULER_JOBS views.

It is perfectly valid for running jobs to alter their own job attributes using the SET_ATTRIBUTE procedure, however, these changes will not be picked up until the next scheduled run of the job.

See Oracle Database PL/SQL Packages and Types Reference for detailed information about the SET_ATTRIBUTE procedure and "Configuring the Scheduler".