Merge statement performance issue on RAC enviornment

Problem description:

Merge statement has fluctuating performance issue in RAC database.


Cause of the Problem:

Merge statment request blocks from different nodes

Solution of the Problem:

It is recommended to run merge in one singe node, and it is doable in RAC to make sure the connection to one node only.

1. add service RAC_S
srvctl add service -d RAC -s RAC_S -r RAC1 -a RAC2 

2. start service RAC_S
srvctl start service -d RAC -s RAC_S

3. check service status
srvctl status service -d RAC -s RAC_S

4. Verify service is added to RAC database
SQL> show parameter servcie