Certain queries don't work and metric name suggestions are wrong

[u39kun]

1. Certain queries don't work. For example, a query cannot contain multiple components, or multiple hosts.
2. The suggested metric names are sometimes incorrect. The metric names are specific to components, but they are cached at the service level, so it always shows the metric names for the first component that you accessed. For example, if the metric names were shown for NAMENODE first, then even if you select the DATANODE component, the metric names for NAMENODE are always shown.