Hi, > 2. The "LEVEL" count from "root" no matter what users input: > count timeseries root.sg1 group by level=2
I prefer this one, in which level is the global level from root. root is the level 0. No matter which one we choose, we should make our documents clear for users and give some examples. Thanks. -- Jialin Qiao School of Software, Tsinghua University 乔嘉林 清华大学 软件学院 > -----原始邮件----- > 发件人: "Jack Tsai" <jack870...@outlook.com> > 发送时间: 2019-09-27 07:41:45 (星期五) > 收件人: "dev@iotdb.apache.org" <dev@iotdb.apache.org> > 抄送: > 主题: 回覆: Add interfaces for querying device or timeseries number > > 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 <jack870...@outlook.com> > 寄件日期: 2019年9月23日 下午 10:35 > 收件者: dev@iotdb.apache.org <dev@iotdb.apache.org> > 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 <jack870...@outlook.com> > 寄件日期: 2019年8月23日 下午 04:00 > 收件者: dev@iotdb.apache.org <dev@iotdb.apache.org> > 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
