Operate on timestamps with Flux
Every point stored in InfluxDB has an associated timestamp. Use Flux to process and operate on timestamps to suit your needs.
- Convert timestamp format
- Calculate the duration between two timestamps
- Retrieve the current time
- Normalize irregular timestamps
- Use timestamps and durations together
If you’re just getting started with Flux queries, check out the following:
- Get started with Flux for a conceptual overview of Flux and parts of a Flux query.
- Execute queries to discover a variety of ways to run your queries.
Convert timestamp format
Unix nanosecond to RFC3339
Use the time() function
to convert a Unix nanosecond timestamp
to an RFC3339 timestamp.
time(v: 1568808000000000000)
// Returns 2019-09-18T12:00:00.000000000Z
RFC3339 to Unix nanosecond
Use the uint() function
to convert an RFC3339 timestamp to a Unix nanosecond timestamp.
uint(v: 2019-09-18T12:00:00.000000000Z)
// Returns 1568808000000000000
Calculate the duration between two timestamps
Flux doesn’t support mathematical operations using time type values. To calculate the duration between two timestamps:
- Use the
uint()function to convert each timestamp to a Unix nanosecond timestamp. - Subtract one Unix nanosecond timestamp from the other.
- Use the
duration()function to convert the result into a duration.
time1 = uint(v: 2019-09-17T21:12:05Z)
time2 = uint(v: 2019-09-18T22:16:35Z)
duration(v: time2 - time1)
// Returns 25h4m30s
Flux doesn’t support duration column types.
To store a duration in a column, use the string() function
to convert the duration to a string.
Retrieve the current time
Current UTC time
Use the now() function to
return the current UTC time in RFC3339 format.
now()
now() is cached at runtime, so all instances of now() in a Flux script
return the same value.
Current system time
Import the system package and use the system.time() function
to return the current system time of the host machine in RFC3339 format.
import "system"
system.time()
system.time() returns the time it is executed, so each instance of system.time()
in a Flux script returns a unique value.
Normalize irregular timestamps
To normalize irregular timestamps, truncate all _time values to a specified unit
with the truncateTimeColumn() function.
This is useful in join()
and pivot()
operations where points should align by time, but timestamps vary slightly.
data
|> truncateTimeColumn(unit: 1m)
Input:
| _time | _value |
|---|---|
| 2020-01-01T00:00:49Z | 2.0 |
| 2020-01-01T00:01:01Z | 1.9 |
| 2020-01-01T00:03:22Z | 1.8 |
| 2020-01-01T00:04:04Z | 1.9 |
| 2020-01-01T00:05:38Z | 2.1 |
Output:
| _time | _value |
|---|---|
| 2020-01-01T00:00:00Z | 2.0 |
| 2020-01-01T00:01:00Z | 1.9 |
| 2020-01-01T00:03:00Z | 1.8 |
| 2020-01-01T00:04:00Z | 1.9 |
| 2020-01-01T00:05:00Z | 2.1 |
Use timestamps and durations together
Add a duration to a timestamp
date.add()
adds a duration to a specified time and returns the resulting time.
import "date"
date.add(d: 6h, to: 2019-09-16T12:00:00Z)
// Returns 2019-09-16T18:00:00.000000000Z
Subtract a duration from a timestamp
date.sub()
subtracts a duration from a specified time and returns the resulting time.
import "date"
date.sub(d: 6h, from: 2019-09-16T12:00:00Z)
// Returns 2019-09-16T06:00:00.000000000Z
Shift a timestamp forward or backward
The timeShift() function adds the specified duration of time to each value in time columns (_start, _stop, _time).
Shift forward in time:
from(bucket: "example-bucket")
|> range(start: -5m)
|> timeShift(duration: 12h)
Shift backward in time:
from(bucket: "example-bucket")
|> range(start: -5m)
|> timeShift(duration: -12h)
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