KB14159: Report does not hit cache in a clustered environment when executed from the node that did not create the cache in MicroStrategy Intelligence Server.

SYMPTOM:
When executing a report from a node that did not create the cache in a clustered environment, the report does not hit cache created on another node and the report is executed against the warehouse in Strategy Intelligence Server.
 
STEPS TO REPRODUCE:
Follow the steps below to reproduce this issue in the Strategy Tutorial project:
 

• Login to node 1 of the cluster and execute a report. A cache is created as displayed in the Cache Monitor, as shown below:
  

• From the same node, execute the report again. It will hit the cache and the Hit Count and Last Hit Time are updated, as shown below:
  

• Now, login to node 2 of the cluster. Again, execute the same report. After executing the report, go to SQL view of this report. It clearly shows that the report did not hit the cache, as shown below:
  

• Now, check the Cache Monitor on node 2 and a new cache is created for this report on this node, as shown below:
  

• However, the cache does not exist on node 1 anymore when checking the Cache Monitor on node 1.

CAUSE:
This issue occurs because the Cache Backup Frequency is set to a high value. For example, the Cache Backup Frequency is set to 15 minutes. This means that the cache created on node 1 is not written into disk for the next 15 minutes. Within these 15 minutes, if the same report is executed from node 2, it cannot hit the cache, as this cache is not being shared yet and still exists only in the memory of node 1. As a result, the report is executed against the warehouse and a new cache is created on node 2. When this happens, the cache created on node 1 gets invalidated and the cache is deleted from the first node.
 
ACTION:
The issue can be resolved by changing the Cache Backup Frequency to 0 minutes. Follow the steps below to change this setting:
 

• Login to the 3-tier project source and right-click on it. Select Configure Strategy Intelligence Server.
• Expand Server Definition and select Advanced.
• Change the value of Backup Frequency (minutes) to '0', as shown below:
  

• Click on OK. This setting change will require a re-start of the Strategy Intelligence Server machine.

Once the setting is changed to a value of '0', the report cache will be written to disk immediately. Thus, when the report is executed from the node that did not create the cache, it will hit the cache created on node 1.