Hi, I want to make a discussion about the interfaces about querying the number of timeseries.
Now, there are two kinds of implementation for users to make a query. Example: The following querying results are both the timeseries number of root.sg1 1. The "LEVEL" count from the user specified prefix: count timeseries root.sg1 group by level=1 2. The "LEVEL" count from "root" no matter what users input: count timeseries root.sg1 group by level=2 If you have any advice, please welcome to discuss with me. I need an instruction to make this decision. Best, Tsung-Han Tsai ________________________________ 寄件者: Jack Tsai <[email protected]> 寄件日期: 2019年9月23日 下午 10:35 收件者: [email protected] <[email protected]> 主旨: 回覆: Add interfaces for querying device or timeseries number Hi, I have found the bug inside this querying function which I have initially implemented. I did not consider the path condition that users might defined and all the paths start from root. This should be started from the path which has been specified. There is an example below: So far, users could only get the timeseries number and the device number from root, which looks like this: count timeseries root group by level=3 and if users enter count timeseries root.sg1 group by level=3 Then it will appear the same answer. For this reason, I will change the underlying implementation of this querying interface to improve the users experience. Best regards, Tsung-Han Tsai ________________________________ 寄件者: Jack Tsai <[email protected]> 寄件日期: 2019年8月23日 下午 04:00 收件者: [email protected] <[email protected]> 主旨: Add interfaces for querying device or timeseries number 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
