What are Nodeapps Services in Oracle RAC

Nodeapps are standard set of oracle application services which are started automatically for RAC.

Node apps Include:

1) VIP.
2) Oracle Net listener.
3) Global Service Daemon.
4) Oracle Notification Service.

Nodeapp Services run on each node of the cluster and will switched over to other nodes through VIP during the failover.


Useful commands to maintain nodeapps services:

srvctl stop nodeapps -n NODE1 
[ STOP NODEAPPS  on NODE 1 ]
srvctl stop nodeapps -n NODE2            
[ STOP NODEAPPS  on NODE 2 ]

srvctl start nodeapps -n NODE1              
[ START NODEAPPS on NODE1  ]
srvctl start nodeapps -n NODE2             
[  START NODEAPPS ON NODE2 ]

srvctl status nodeapps                      
[Check the status of services on all nodes]

SQL Profile and SQL Plan Baseline

What is SQL Profile?

A SQL profile contains corrections for poor optimizer estimates discovered by the SQL Tuning advisor.A  SQL profile is to a SQL statement what statistics are to a table or index.
Implementing sql profiles allows us to replace bad sql execution plan with good execution plan.



What is SQL Plan Baseline?

A SQL plan baseline for a SQL statement consists of a set of accepted plans. When the statement is parsed, the optimizer will only select the best plan from among this set. If a different plan is found using the normal cost-based selection process, the optimizer will add it to the plan history but this plan will not be used until it is verified to perform better than the existing accepted plan and is evolved.