3 ms·

By "temporal model" do you mean relational tables of "customer X used Y amount of this resource at price Z from timestamp A to timestamp B" or ... ?

by gnat 4y ago

benwilson-512 4y ago
In field metering situations you can have the timeline of each meter, when it records data points, and then you have the different timeline of the backend service, when it actually _receives_ data points. Bonus points if the meters can send data out of order.
- gnat 4y ago
  Ah, thanks. OMFG and I thought our billing was hard. You're in my thoughts and prayers!
- ntr-- 4y ago
  I did a tender for aggregating events and emitting notifications from a fleet of transport vehicles that reported metrics over LTE. When connected they would emit events as they happened, but when there was poor service or disconnection they would buffer them and send them as a burst once they reconnected... in reverse order. I forget the finer details, but the service I was writing was supposed to notify of trucks entering and leaving geofences, inactivity etc. anything you can think of where the order of events is important.
- girvo 4y ago
  You just perfectly described what I’m currently working on. And it’s even more complex than you’ve explained (which I’m sure you’d well know haha)
jimsparkman 4y ago
I assume they are using something like DB2, which has very specific meaning when it comes to temporal or bitemporal tables. https://www.ibm.com/docs/en/db2/10.5?topic=tables-bitemporal https://www.ibm.com/docs/en/db2/10.5?topic=tables-bitemporal
- janci 4y ago
  Not DB2, but the meaning is the same. In a time-series (or event) table you have one date - when the data point is valid (event occurred). In a temporal table you have two dates - interval when the data is valid. In a bitemporal table you have two intervals. First describes when the data is valid in real world, the second when does the system know about the real-world state. I.e. if company changed address on 2022-05-01 but the system will not get that information until three day later (2022-05-03) you have two validity intervals. Then you may ask - what was the company address on 2022-05-02? And what did the system think the address was on 2022-05-02? You will get two different answers. This is important if you need e.g. to make a correction to previously issued invoice. You need to know what data was used for original invoice and what data should have been used.

By "temporal model" do you mean relational tables of "customer X used Y amount of this resource at price Z from timestamp A to timestamp B" or ... ?

by gnat 4y ago

By "temporal model" do you mean relational tables of "customer X used Y amount of this resource at price Z from timestamp A to timestamp B" or ... ?

benwilson-512 4y ago

In field metering situations you can have the timeline of each meter, when it records data points, and then you have the different timeline of the backend service, when it actually _receives_ data points. Bonus points if the meters can send data out of order.

gnat 4y ago
Ah, thanks. OMFG and I thought our billing was hard. You're in my thoughts and prayers!
ntr-- 4y ago
I did a tender for aggregating events and emitting notifications from a fleet of transport vehicles that reported metrics over LTE. When connected they would emit events as they happened, but when there was poor service or disconnection they would buffer them and send them as a burst once they reconnected... in reverse order. I forget the finer details, but the service I was writing was supposed to notify of trucks entering and leaving geofences, inactivity etc. anything you can think of where the order of events is important.
girvo 4y ago
You just perfectly described what I’m currently working on. And it’s even more complex than you’ve explained (which I’m sure you’d well know haha)

jimsparkman 4y ago

I assume they are using something like DB2, which has very specific meaning when it comes to temporal or bitemporal tables. https://www.ibm.com/docs/en/db2/10.5?topic=tables-bitemporal https://www.ibm.com/docs/en/db2/10.5?topic=tables-bitemporal

janci 4y ago
Not DB2, but the meaning is the same. In a time-series (or event) table you have one date - when the data point is valid (event occurred). In a temporal table you have two dates - interval when the data is valid. In a bitemporal table you have two intervals. First describes when the data is valid in real world, the second when does the system know about the real-world state. I.e. if company changed address on 2022-05-01 but the system will not get that information until three day later (2022-05-03) you have two validity intervals. Then you may ask - what was the company address on 2022-05-02? And what did the system think the address was on 2022-05-02? You will get two different answers. This is important if you need e.g. to make a correction to previously issued invoice. You need to know what data was used for original invoice and what data should have been used.