A Tale of 4 Schedulers…

A long time ago in a galaxy far, far away, there was only one Oracle scheduler. It was managed using the DBMS_JOB package and the job information was stored in a single table.

SELECT table_name
FROM   dba_tables
WHERE  owner = 'SYS'
AND    table_name LIKE 'JOB$%'
ORDER BY table_name;

TABLE_NAME
------------------------------
JOB$

1 row selected.

SQL>

Information about scheduled jobs was available from the “DBA_JOBS%” views.

SELECT view_name
FROM   dba_views
WHERE  owner = 'SYS'
AND    view_name LIKE 'DBA_JOBS%'
ORDER BY view_name;

VIEW_NAME
------------------------------
DBA_JOBS
DBA_JOBS_RUNNING

2 rows selected.

SQL>

Oracle 10g introduced a new scheduler that was managed using the DBMS_SCHEDULER package, whose job information was stored in the “SCHEDULER$%” tables.

SELECT table_name
FROM   dba_tables
WHERE  owner = 'SYS'
AND    table_name LIKE 'SCHEDULER$%'
ORDER BY table_name;

TABLE_NAME
------------------------------
SCHEDULER$_CHAIN
.
.
.
SCHEDULER$_WINGRP_MEMBER

22 rows selected.

SQL>

Information about scheduled jobs for this new scheduler was available from the “DBA_SCHEDULER%” views.

SELECT view_name
FROM   dba_views
WHERE  owner = 'SYS'
AND    view_name LIKE 'DBA_SCHEDULER%'
ORDER BY view_name;

VIEW_NAME
------------------------------
DBA_SCHEDULER_CHAINS
.
.
.
DBA_SCHEDULER_WINGROUP_MEMBERS

19 rows selected.

SQL>

In addition to the two internal schedulers, the OEM 10g DBConsole had its own scheduler, which stored job information in the “MGMT_JOB%” tables.

SELECT table_name
FROM   dba_tables
WHERE  owner = 'SYSMAN'
AND    table_name LIKE 'MGMT_JOB%'
ORDER BY table_name;

TABLE_NAME
------------------------------
MGMT_JOB
.
.
.
MGMT_JOB_VALUE_PARAMS

44 rows selected.

SQL>

To confuse matters further, the OEM 10g Grid Control repository had a similar scheduler to OEM 10g DBConsole, but with a few extra tables.

SELECT table_name
FROM   dba_tables
WHERE  owner = 'SYSMAN'
AND    table_name LIKE 'MGMT_JOB%'
ORDER BY table_name;

TABLE_NAME
------------------------------
MGMT_JOB
.
.
.
MGMT_JOB_VALUE_PARAMS

53 rows selected.

SQL>

Faced with the choice of four ways to schedule a job, most DBAs called “Tim Hall” decided to pick a single scheduler and keep things simple :)

Cheers

Tim…

PS. Don’t even get me started on OS schedulers and the Oracle Applications scheduler… ;)

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