ORACLE DATABASE RESOURCE MANAGER

BROAD STEPS

1. Create Pending area – (Automatic if using EM)- either Grid control or DB control.

2. Create a resource consumer group – Grouping of users who will receive the same amount of resources.

3. Create a Resource plan – This is a collection of directives that specify how Oracle should allocate resources to consumer groups.

4. Create a plan directive – This associates resource consumer groups with resource plans and allocates resources amongst resource consumer groups.

5. Validate the pending area - (Automatic if using EM)- either Grid control or DB control

6. Submit the pending area - (Automatic if using EM)- either Grid control or DB control

We will use EM to carry out these tasks –

Login to rac database db control page –

https://xxxxxxx.xxxxxxxx.com:1158/em/console

Login as sys/xxxxxx

Go to racdev1 instance on home page under Instances –

Click on Server .

Next create a consumer group – click on Consumer groups

Enter Object name OOAS and click on create.

Enter consumer group name and description – and click OK.

Confirmation on screen –

Exit to Server page –

Next Create a resource plan .

Click on Plans

Object name – OAAS_PLAN and Create –

OK

Confirmation received.

Next create a plan directive –

Back to Server page –

Click on Plans

Click on OAAS_PLAN radio button and then on VIEW

As you can see OTHER_GROUPS is a default resource consumer group which must be assigned – otherwise a plan cannot be submitted to the Pending area.

Now we will assign another resource consumer group to the OAAS_PLAN.

Click on Edit on the right hand bottom –

Click on Advanced and then on Modify –

Move OAAS consumer group and click OK.

Now OAAS group is part of the OAAS_PLAN directive.

Now various resource allocations can be controlled – click on all tabs – ex General, Parallelism, Session Pool etc.

We will choose Session Pool to control the number of Active sessions for this plan.

We can control the number of active sessions for each user assigned to this consumer group via this plan.

For example we say only 2 active sessions are allowed –

Click on Show Sql –

BEGINdbms_resource_manager.clear_pending_area();dbms_resource_manager.create_pending_area();dbms_resource_manager.create_plan_directive(    plan => ?,    group_or_subplan => ?,

    comment => ?,    mgmt_p1 => ?, mgmt_p2 => ?, mgmt_p3 => ?, mgmt_p4 => ?,    mgmt_p5 => ?, mgmt_p6 => ?, mgmt_p7 => ?, mgmt_p8 => ? ,    parallel_degree_limit_p1 => ? ,    switch_io_reqs => ? ,   switch_io_megabytes => ? ,    active_sess_pool_p1 => ?,    queueing_p1 => ?,    switch_group => ?,    switch_time => ?,    switch_estimate => case ? when 'false' then false when 'true' then true else false end,    max_est_exec_time => ?,    undo_pool => ? ,    max_idle_time => ?,    max_idle_blocker_time => ?,    switch_for_call => case ? when 'false' then false when 'true' then true else false end

);dbms_resource_manager.submit_pending_area();END; Apply.

Click Return and then Apply –

Confirmation that plan has been modified.

In this case only 2 active sessions of users assigned to the OAAS group can run transactions, a third session will remain in the queue for 300 seconds ( 5 minutes ) before getting disconnected.

Apply

Now we will have to assign users to the particular consumer group.

Back to HOME PAGE – Server tab.

Click on Users under Secuirty.

Click on Selection Mode drop down and change to Multiple.

Now click on radio button against 3 users – HR

CLICK ON HR

Click Edit

Click on Consumer group privileges, then on Edit list and choose OOAS as consumer group to be attached to.

OK –

Also make the default consumer group OAAS.

Show sql –

BEGIN    dbms_resource_manager_privs.grant_switch_consumer_group(         grantee_name => 'HR',        consumer_group => 'OAAS',        grant_option => FALSE    );END;

BEGIN     dbms_resource_manager.set_initial_consumer_group(         user => 'HR',        consumer_group => 'OAAS'    );END;

Return

Apply.

Activate OAAS_PLAN –

Server – plans

CLICK ON OAAS_PLAN and then activate – go.

Confirmation.

Now test –

Login as HR and run 3 different queries – the third query must queued up and then be killed after 5 minutes of waiting.

I ran 3 sessions after logging in as HR –

On first look they all seemed active – however after 5 minutes, the last session was killed with the following error.

SQL> @loop 14 /declare*ERROR at line 1:ORA-07454: queue timeout, 300 second(s), exceeded

SQL>

SQL> select resource_consumer_group,status from v$session where username='HR';

RESOURCE_CONSUMER_GROUP STATUS-------------------------------- --------OAAS ACTIVEOAAS ACTIVEOAAS ACTIVE

After resource manager killed the session –

SQL> select resource_consumer_group,status from v$session where username='HR';

RESOURCE_CONSUMER_GROUP STATUS-------------------------------- --------OAAS INACTIVEOAAS ACTIVEOAAS ACTIVE

Therefore the Resource manager made sure that no more than 2 active sessions were allowed at one time for HR user logins.

This can now be incorporated for other users…..more plans can be added if necessary.

@sessions –

HR oracle 406 58655 733346 ACTIVE 2990 816 SQL*Plus devu044n1 sqlplus@devu044n1 (TNS V1-V3) 18-Aug-2010 09:03:58

HR oracle 404 64015 258248 INACTIVE 1838 304 SQL*Plus devu044n1 sqlplus@devu044n1 (TNS V1-V3) 18-Aug-2010 09:06:27

HR oracle 598 6591 712782 ACTIVE 2094 304 SQL*Plus devu044n1 sqlplus@devu044n1 (TNS V1-V3) 18-Aug-2010 09:06:53

Kill -9 258248 to kill inactive session.