Hi Trevor, Now there is no `group by device` in IoTDB, what you want may be the `align by device` clause.
Best regards, ----------------------- Yuan Tian On Fri, Feb 16, 2024 at 5:48 AM Trevor Hart <tre...@ope.nz> wrote: > Would it not be better to utilise the hierarchy in IoTDB? This saves space > and means no need for a key > > > > So > > > > root.vehicles.CAR1 > > root.vehicles.CAR2 > > root.vehicles.CAR3 > > > > And then under each CAR store lat, long, speed etc > > > > You can still query all of the data > > > > select * from root.vehicles.* > limit 1000 > group by device > > > > That way the key is part of the schema and not a measurement. > > > I use a similar model for storing server metrics (CPU, RAM, DISK etc) > > > > Thanks > > > > > ---- On Tue, 16 Jan 2024 22:09:19 +1300 Xiangdong Huang < > saint...@gmail.com> wrote --- > > > > Hi Cheongu Kim, > > Please send email to mailto:dev@iotdb.apache.org for discussion (remember > to > subscribe the mailing list first). > > As for your question, maybe the easiest method is add an offset on the > timestamp to make they different. > e.g., > origin data: <car_1, 1705396048000, 2.0>, <car_1, 1705396048000, 2.1>, > <car_1, 1705396049000, 2.2> > to: > <car_1, 1705396048000, 2.0>, <car_1, 1705396048001, 2.1>, <car_1, > 1705396049000, 2.2> > > Best, > ----------------------------------- > Xiangdong Huang > School of Software, Tsinghua University > > > 김천구 <mailto:ckim191...@gmail.com> 于2024年1月16日周二 02:33写道： > > > > > Dear Apache IoTDB Development Team > > > > Greetings, I hope this email finds you well. My name is Cheongu Kim and > I am reaching out to you today to request some assistance. I currently plan > to test IoTDB with some spatio-temporal(so-called ST) dataset which > consists of time, longitude, latitude, and serial data generated from these > 3 elements. > > > > Since the data is about trajectories of vehicles, there are hundreds of > duplicates at the same time even in one vehicle because of its measurement > method. And the dataset can be identified by the serial data(Since space > and time are unique) > > > > I need to make a database which can be identified by the serial data, > Which means the serial data must be a key column or at least make sure not > to lose the data because it has the same time value or timestamp. > > > > I read about IoTDB papers, and explored the website but was unable to > find the information about creating the key column or unique column. I know > it's a time series database so time is the key column but how can I make > another key or unique column in iotdb? > > > > Thank you in advance for your time and assistance. I look forward to any > insights or information you can provide. > > > > Sincerely, > > > > Cheongu Kim > > mailto:ckim191...@gmail.com
