+1, this feature is useful.
-----------------------------------
Xiangdong Huang
School of Software, Tsinghua University
黄向东
清华大学 软件学院
Eric Pai <ericpa...@hotmail.com> 于2022年6月16日周四 17:45写道：
> Good idea! If we can make use of the tags not only in metadata but also in
> data query, we can enrich the data analysis ability a lot, and help the
> business layer to achieve more goals than before. However as the query
> grammar may become more complicated, we should take the easy-use into
> consideration of SQL design as well.
>
> 在 2022/6/16 17:39，“Wz”<zhongwang...@qq.com.INVALID> 写入:
>
> Hi guys,
>
>
>
>
> I believe using tags to do data filtering and aggregation can be a
> common need. Putting all the attributes into the path is not a good idea
> because it makes the path extremely long, and slows down the MTree
> searching, so we take some of the attributes as tags. But that doesn't mean
> tags are not important.
>
>
>
>
>
> Let's take the following ECS management scenario as an example. IoTDB
> stores the cpu_util of each ECS instance. Besides that, an ECS instance has
> static attributes like region_id, available_zone, hostname, CPU, memory,
> storage, and OS store. Since the CPU, memory, and storage are numbers and
> OS is a string with white spaces, they are stored as tags and other
> attributes are stored as levels in the path like
> root.${region_id}.${available_zone}.${hostname}.cpu_util.
>
>
>
>
> Let's say there are some ECS instances whose cpu_util is abnormally
> high in the last hour and we want to know if the problem is caused by a
> certain version of OS. The query should be like,
>
>
>
>
> > SELECT OS, COUNT(cpu_util) FROM root.** WHERE cpu_util > 95.0
> GRUOP BY TAG OS ALIGN BY DEVICE
>
>
>
>
> With the ability to do filter and aggregation with tags, IoTDB can be
> more powerful in analytics processing. What do you think?
>
>
>
>
> Any suggestions are welcome :D
>
>
>
>
> Zhong Wang,
>
> Alibaba group
>
>
