Hi, I have finished the implementation of this improvement as adding interfaces for querying device or timeseries number (the corresponding JIRA issue: https://issues.apache.org/jira/browse/IOTDB-174).
I have created three sql command for users to done such operations mentioned in the issue, which would be shown below. Let's take a look with an example. There are 8 timeseries under the root, which are: root.vehicle1.d1.s1, root.vehicle1.d1.s2, root.vehicle1.d2.s3, root.vehicle1.d2.s4, root.vehicle2.d3.s5, root.vehicle2.d3.s6, root.vehicle2.d4.s7, root.vehicle2.d4.s8 1. The interface for querying the timeseries number under the specified path. COUNT TIMESERIES <path> According to the example above: COUNT TIMESERIES root Result: |Timeseries Num| |8 | 2. The interface for querying the node number at the given level in current Metadata Tree (this could be used to query the number of devices) COUNT NODES <path> LEVEL=<integer> According to the example above: COUNT NODES root LEVEL=3 Result: |Node Num| |4 | 3. The interface for querying the timeseries number of each node at the given level (this could be used to query the number of sensors under each device) COUNT TIMESERIES <path> GROUP BY LEVEL = <integer> According to the example above: COUNT TIMESERIES root GROUP BY LEVEL = 3 Result: |Node Path |Node Timeseries Num| |root.vehicle.d1|2 | |root.vehicle.d2|2 | |root.vehicle.d3|2 | |root.vehicle.d4|2 | These three interfaces could provide users more query options. Best regards, Tsung-Han Tsai
