mirror of
https://github.com/prometheus/prometheus.git
synced 2024-11-09 23:24:05 -08:00
49 lines
1.8 KiB
Markdown
49 lines
1.8 KiB
Markdown
---
|
||
title: Disabled Features
|
||
sort_rank: 10
|
||
---
|
||
|
||
# Disabled Features
|
||
|
||
Here is a list of features that are disabled by default since they are breaking changes or are considered experimental.
|
||
Their behaviour can change in future releases which will be communicated via the [release changelog](https://github.com/prometheus/prometheus/blob/main/CHANGELOG.md).
|
||
|
||
You can enable them using the `--enable-feature` flag with a comma separated list of features.
|
||
They may be enabled by default in future versions.
|
||
|
||
## `@` Modifier in PromQL
|
||
|
||
`--enable-feature=promql-at-modifier`
|
||
|
||
The `@` modifier lets you specify the evaluation time for instant vector selectors,
|
||
range vector selectors, and subqueries. More details can be found [here](querying/basics.md#modifier).
|
||
|
||
## Expand environment variables in external labels
|
||
|
||
`--enable-feature=expand-external-labels`
|
||
|
||
Replace `${var}` or `$var` in the [`external_labels`](configuration/configuration.md#configuration-file)
|
||
values according to the values of the current environment variables. References
|
||
to undefined variables are replaced by the empty string.
|
||
|
||
## Negative offset in PromQL
|
||
|
||
This negative offset is disabled by default since it breaks the invariant
|
||
that PromQL does not look ahead of the evaluation time for samples.
|
||
|
||
`--enable-feature=promql-negative-offset`
|
||
|
||
In contrast to the positive offset modifier, the negative offset modifier lets
|
||
one shift a vector selector into the future. An example in which one may want
|
||
to use a negative offset is reviewing past data and making temporal comparisons
|
||
with more recent data.
|
||
|
||
More details can be found [here](querying/basics.md#offset-modifier).
|
||
|
||
## Remote Write Receiver
|
||
|
||
`--enable-feature=remote-write-receiver`
|
||
|
||
The remote write receiver allows Prometheus to accept remote write requests from other Prometheus servers. More details can be found [here](storage.md#overview).
|
||
|