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Query InfluxDB with Flux

This guide walks through the basics of using Flux to query data from InfluxDB. Every Flux query needs the following:

  1. A data source
  2. A time range
  3. Data filters

1. Define your data source

Flux’s from() function defines an InfluxDB data source. It requires a bucket parameter. The following examples use example-bucket as the bucket name.

from(bucket:"example-bucket")

2. Specify a time range

Flux requires a time range when querying time series data. “Unbounded” queries are very resource-intensive and as a protective measure, Flux will not query the database without a specified range.

Use the pipe-forward operator (|>) to pipe data from your data source into range(), which specifies a time range for your query. It accepts two parameters: start and stop. Start and stop values can be relative using negative durations or absolute using timestamps.

Example relative time ranges
// Relative time range with start only. Stop defaults to now.
from(bucket:"example-bucket")
    |> range(start: -1h)

// Relative time range with start and stop
from(bucket:"example-bucket")
    |> range(start: -1h, stop: -10m)

Relative ranges are relative to “now.”

Example absolute time range
from(bucket:"example-bucket")
    |> range(start: 2021-01-01T00:00:00Z, stop: 2021-01-01T12:00:00Z)

Use the following:

For this guide, use the relative time range, -15m, to limit query results to data from the last 15 minutes:

from(bucket:"example-bucket")
    |> range(start: -15m)

3. Filter your data

Pass your ranged data into filter() to narrow results based on data attributes or columns. filter() has one parameter, fn, which expects a predicate function evaluates rows by column values.

filter() iterates over every input row and structures row data as a Flux record. The record is passed into the predicate function as r where it is evaluated using predicate expressions.

Rows that evaluate to false are dropped from the output data. Rows that evaluate to true persist in the output data.

// Pattern
(r) => (r.recordProperty comparisonOperator comparisonExpression)

// Example with single filter
(r) => (r._measurement == "cpu")

// Example with multiple filters
(r) => r._measurement == "cpu" and r._field != "usage_system")

Use the following:

For this example, filter by the cpu measurement, usage_system field, and cpu-total tag value:

from(bucket: "example-bucket")
    |> range(start: -15m)
    |> filter(fn: (r) => r._measurement == "cpu" and r._field == "usage_system" and r.cpu == "cpu-total")

4. Yield your queried data

yield() outputs the result of the query.

from(bucket: "example-bucket")
    |> range(start: -15m)
    |> filter(fn: (r) => r._measurement == "cpu" and r._field == "usage_system" and r.cpu == "cpu-total")
    |> yield()

Flux automatically assumes a yield() function at the end of each script to output and visualize the data. Explicitly calling yield() is only necessary when including multiple queries in the same Flux query. Each set of returned data needs to be named using the yield() function.

Congratulations!

You have now queried data from InfluxDB using Flux.

The query shown here is a basic example. Flux queries can be extended in many ways to form powerful scripts.


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Set your InfluxDB URL

Linux Package Signing Key Rotation

All signed InfluxData Linux packages have been resigned with an updated key. If using Linux, you may need to update your package configuration to continue to download and verify InfluxData software packages.

For more information, see the Linux Package Signing Key Rotation blog post.

InfluxDB Cloud backed by InfluxDB IOx

All InfluxDB Cloud organizations created on or after January 31, 2023 are backed by the new InfluxDB IOx storage engine. Check the right column of your InfluxDB Cloud organization homepage to see which InfluxDB storage engine you’re using.

If powered by IOx, this is the correct documentation.

If powered by TSM, see the TSM-based InfluxDB Cloud documentation.

InfluxDB Cloud backed by InfluxDB TSM

All InfluxDB Cloud organizations created on or after January 31, 2023 are backed by the new InfluxDB IOx storage engine which enables nearly unlimited series cardinality and SQL query support. Check the right column of your InfluxDB Cloud organization homepage to see which InfluxDB storage engine you’re using.

If powered by TSM, this is the correct documentation.

If powered by IOx, see the IOx-based InfluxDB Cloud documentation.

State of the InfluxDB Cloud (IOx) documentation

The new documentation for InfluxDB Cloud backed by InfluxDB IOx is a work in progress. We are adding new information and content almost daily. Thank you for your patience!

If there is specific information you’re looking for, please submit a documentation issue.