If the cluster is down and a query is executed, the first query triggers the cluster startup process, and all queries fail until the cluster is up and running. In this case, the following messages are displayed:
Message 1: "Could not serve the query as Query Engine Cluster is not available. Query Engine is launched. Please try after some time."
Message 2: "Could not serve the query as Query Engine Cluster is starting. Please try after some time."
By default, the queries fail until Query Engines are started. If you want to hold the queries when query engines are down, you can specify the time (in minutes) for holding queries by using the QE_STARTUP_QUERY_HOLD_TIME property.
Ensure that if the query engines become active before the configured time, the query will be served; otherwise, it will fail.
The Query Engines do not start for any ROLAP queries.
During the transitioning period of Query Engines; such as scale-up, scale-down, or shut down; you can design and refine the semantic model because the Coordination Master is always up and running .
The capacity of the BI Servers cannot be changed.
All BI Servers can be shut down except the Coordination Master. If there is only one BI Server, this BI Server is treated as the Coordination Master.
The Settings option and Add Schedule option are disabled on the Load screen.
You can view on-screen notifications that provide you with timely information about the state of the cluster.
When you scale down the Query Engines, you reduce the capacity of the node, including the number of cores and memory. Conversely, when you scale up the Query Engines, you increase the capacity of the node by adding more cores and memory.
The Query Engines do not start for any ROLAP queries.
During the transitioning period of Query Engines; such as scale-up, scale-down, or shut down; you can design and refine the semantic model because the Coordination Master is always up and running .
