最近在一个测试环境中建立物化视图远程同步环境，但是远程视图一直未按照预期的时间进行刷新。以至于一开始让我怀疑ONDEMAND与STARTWITHNEXTBY冲突。但再三确认，发现是我的测试环境中ora_cjq0进程不存在，唉!开始怎么不往这方面去想呢，修改一下JOB_QUEUE_PROCESSES参数，一切恢复正常,突然发现ORACLE JOB方面的问题还不少，贴一篇METALINK文章，历数以前碰到的JOB失效的原因，无非以下几种：
JobsNotExecuting Automatically文档ID:注释:313102.1
Symptoms
Jobs arenolonger executing automatically.
Ifforced(execdbms_job.run();),theseexecutefine.
Cause
Tryingthemost common reasons why jobs don't execute automatically and as scheduled:
1) Instance in RESTRICTED SESSIONS mode?
Check if the instance is in restricted sessions mode:
select instance_name,logins from v$instance;
If logins=RESTRICTED, then:
alter system disable restricted session;
^-- Checked!
2) JOB_QUEUE_PROCESSES=0
Make sure that job_queue_processes is > 0
show parameter job_queue_processes
^-- Checked!
3) _SYSTEM_TRIG_ENABLED=FALSE
Check if _system_enabled_trigger=false
col parameter format a25
col value format a15
select a.ksppinm parameter,b.ksppstvl value from x$ksppi a,x$ksppcv b
Where a.indx=b.indx and ksppinm=’_system_trig_enabled’;
^-- Checked!
4) Is the job BROKEN?
select job,broken from dba_jobs where job=;
If broken, then check the alert log and trace files to diagnose the issue.
^-- Checked! The job is not broken.