Job Chains

创建chain的顺序

1. 创建chain object；

2. 定义chain中的steps；

3. 增加规则；

4. 启用chain；

5. 创建指向这个chain的job。

创建Chain Object

实验描述：

ENV：create table test_chain(id number);

createtable test_chain1(id number);

createtable test_chain2(id number);

step1：test_chain1表插入一条数据；

step2：step1执行成功后，test_chain中有超过两条数据时，插入test_chain2表一条数据。

begin

dbms_scheduler.create_chain(chain_name=>'my_chain1',rule_set_name=>null,evaluation_interval=>interval '1' minute,

comments=>'Chain with 30 minuteevaluation interval');

end;

/

PL/SQL procedure successfully completed.

evaluation_interval指的是chain rule的扫描间隔，这里是自定义的。Scheduler在启动job chain时和每次执行完chain step时都会去扫描chain rule，这里除了启动job chain时和chain step结束时，还会每一分钟自动扫描一次来判断rule的正确性。这个参数对于某种特殊情形，本次实验就启用这个参数。

定义Chain Steps

创建program

begin

dbms_scheduler.create_program(program_name=>'my_program1',program_type=>'PLSQL_BLOCK',

program_action=>'begin insert intotest_chain1 values (1);commit;end;');

end;

/

PL/SQL procedure successfully completed.

begin

dbms_scheduler.create_program(program_name=>'my_program2',

program_action=>'begin insert intotest_chain2 values (2);commit;end;');

end;

/

PL/SQL procedure successfully completed.

--enable program

SQL> begin

2dbms_scheduler.enable('my_program1,my_program2');

3 end;

4 /

创建step

begin

dbms_scheduler.define_chain_step(chain_name=>'my_chain1',step_name=>'my_step1',program_name=>'my_program1');

dbms_scheduler.define_chain_step(chain_name=>'my_chain1',step_name=>'my_step2',program_name=>'my_program2');

end;

/

PL/SQL procedure successfully completed.

Note：定义step时，program和chain可以不存在，但是启动chain时，必须保证program

和chain存在。

增加Chain规则

Rule描述：

step1直接执行；

step2执行条件：step1执行成功，并且(selectcount(*) from test_chain) >=2

begin

dbms_scheduler.define_chain_rule(chain_name=>'my_chain1',condition=>'TRUE',action=>'startmy_step1',rule_name=>'rule_1');

end;

/

PL/SQL procedure successfully completed.

begin

dbms_scheduler.define_chain_rule(chain_name=>'my_chain1',condition=>':my_step1.state=''SUCCEEDED''and (select count(*) from test_chain) >=2',

action=>'startmy_step2',rule_name=>'rule_1_2');

end;

/

PL/SQL procedure successfully completed.

启用Chain

begin

dbms_scheduler.enable('my_chain1');

end;

/

PL/SQL procedure successfully completed.

创建Chain job

Note：直接调用run_chain运行则不需enablechain，创建job则需要。

begin

dbms_scheduler.create_job(job_name=>'chain_job_1',job_type=>'CHAIN',job_action=>'my_chain1',

start_date=>sysdate,repeat_interval=>'freq=minutely;interval=1',enabled=>TRUE);

end;

/

Note：单独启动job，注意参数USE_CURRENT_SESSION=>false

SQL> begin

2dbms_scheduler.run_job(job_name=>'chain_job_1',USE_CURRENT_SESSION=>false);

3 end;

4 /

SQL> selectjob_name,job_subname,status,req_start_date,actual_start_date fromuser_scheduler_job_run_details where job_name='CHAIN_JOB_1';

JOB_NAME JOB_SUBNAME STATUS REQ_START_DATE ACTUAL_START_DATE

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

CHAIN_JOB_1 STOPPED 16-JUN-16 03.44.03.000000 PM +08:00 16-JUN-16 03.44.03.588735 PM+08:00

CHAIN_JOB_1 MY_STEP1 FAILED 16-JUN-16 03.44.03.682508 PM +08:00 16-JUN-16 03.44.03.693946 PM+08:00

CHAIN_JOB_1 MY_STEP1 SUCCEEDED 16-JUN-16 04.17.43.335679 PM +08:00 16-JUN-16 04.17.43.436069 PM+08:00

发现my_step2还没有运行

SQL> select * from test_chain1;

ID

----------

1

my_program1已写入数据

制造my_step2启动的条件

SQL> insert into test_chainvalues(9);

1 row created.

SQL> /

1 row created.

SQL> commit;

Commit complete.

SQL> selectjob_name,actual_start_date fromuser_scheduler_job_run_details where job_name='CHAIN_JOB_1';

JOB_NAME JOB_SUBNAME STATUS REQ_START_DATE ACTUAL_START_DATE

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

CHAIN_JOB_1 STOPPED 16-JUN-16 03.44.03.000000 PM +08:00 16-JUN-16 03.44.03.588735 PM+08:00

CHAIN_JOB_1 MY_STEP2 SUCCEEDED 16-JUN-16 04.30.43.064558 PM +08:00 16-JUN-16 04.30.43.152496 PM+08:00

CHAIN_JOB_1 MY_STEP1 FAILED 16-JUN-16 03.44.03.682508 PM +08:00 16-JUN-16 03.44.03.693946 PM+08:00

CHAIN_JOB_1 MY_STEP1 SUCCEEDED 16-JUN-16 04.17.43.335679 PM +08:00 16-JUN-16 04.17.43.436069 PM+08:00

SQL> select * from test_chain2;

ID

----------

2

（编辑：李大同）

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