Hey Jialin, xinagdong,
very good question!
And I tend to agree with Xiangdong.
If the users do it that way it probably makes most sense for them.
The question I would ask is why "devices" hurt us (I know a bit about the
implementation of course but probably we have to adopt our datamodel also a bit
in the future).
Generally speaking, form e it also makes sense tob e allowed to have
"subcategories" below my devices as my devices usually are "big".
And technically speaking in the current version this is totally possible to
have nested structures below devices or measurements (but these will then again
be devices).
So my question is:
- Do we really need the static construct of a "device" or can we probably use a
different datastructure where I "select" my device only at query time and we
just select everything under that tree as ist measurements or
"sub-measurements" in cases of nesting.
WDYT?
Julian
Am 20.07.20, 09:34 schrieb "Xiangdong Huang" <saint...@gmail.com>:
Hi,
This is a quite good topic!
1. maybe we should hear more users opinions.
For me, I think emphasize the concept of "device" is good. We can even
expose the concept in our APIs.
2.
> A more efficient way is
> root.sg.device1.measurement1_int0
> root.sg.device1.measurement1_int1
> root.sg.device1.measurement1_int2
> root.sg.device1.measurement2_long
I think the more efficient way is:
root.sg.device1.measurement1.0
root.sg.device1.measurement1.1
root.sg.device1.measurement1.2
root.sg.device1.measurement2
And, as you said "a device has a sensor that collects some data in array
format (int[3]) and some in long type",
will the user query just one element from the int[3]? If not, a better
schema is:
root.sg.device1.measurement1 (the dataType is int[])
root.sg.device1.measurement2 (the dataType is long)
Best,
-----------------------------------
Xiangdong Huang
School of Software, Tsinghua University
黄向东
清华大学 软件学院
Jialin Qiao <qj...@mails.tsinghua.edu.cn> 于2020年7月20日周一 下午3:28写道：
> Hi
>
> Recently, I find that some users create timeseries do not following the
> real world semantic of device
>
>
> E.g., a device has a sensor that collects some data in array format
> (int[3]) and some in long type.
>
>
> Many users will create timeseries like this:
>
>
> root.sg.device1.measurement1.int0
> root.sg.device1.measurement1.int1
> root.sg.device1.measurement1.int2
> root.sg.device1.measurement2.long
>
>
> As a consequence, there will be two devices instead of one device. This
> will cause the real number of devices is much bigger than the real devices
> they thought. The drawback is: more devices leads to more memory
> consumption.
>
>
> A more efficient way is
>
>
> root.sg.device1.measurement1_int0
> root.sg.device1.measurement1_int1
> root.sg.device1.measurement1_int2
> root.sg.device1.measurement2_long
>
>
> In this schema, there will be only one device and 4 measurements.
>
>
> The problem is we extract the device id automatically. Users usually do
> not have a clear concept about "device". Should we emphasize the concept
of
> device by letting users create device manually?
>
>
> What do you think?
>
> Thanks,
> --
> Jialin Qiao
> School of Software, Tsinghua University
>
> 乔嘉林
> 清华大学 软件学院
