I have two write points for InfluxDB, one is the start and the other is the end. I just need to determine the duration between those two events, and make queries around it. InfluxDB has difference() aggregate method, but it doesn't work on the time meta field.
Is supplying a custom timestamp value the only way to accomplish this?
If you write only the mentioned two entries then you can follow the below steps -
- Limit the result to two (Eg: select * from timeseries limit 2)
- Extract the time from the result set
- Take the difference between the time
As per "Can I perform mathematical operations against timestamps?"
No:
"Currently, it is not possible to execute mathematical operators against timestamp values in InfluxDB. Most time calculations must be carried out by the client receiving the query results."
and yes, maybe:
The function ELAPSED() returns the difference between subsequent timestamps in a single field.
So it depends on the shape of your data.
来源：https://stackoverflow.com/questions/27959196/calculating-duration-between-a-start-and-end-event-in-influxdb