prometheus/docs/disabled_features.md
Callum Styan 8fd73b1d28
Add Exemplar Remote Write support (#8296)
* Write exemplars to the WAL and send them over remote write.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Update example for exemplars, print data in a more obvious format.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Add metrics for remote write of exemplars.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Fix incorrect slices passed to send in remote write.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* We need to unregister the new metrics.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address review comments

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Order of exemplar append vs write exemplar to WAL needs to change.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Several fixes to prevent sending uninitialized or incorrect samples with an exemplar. Fix dropping exemplar for missing series. Add tests for queue_manager sending exemplars

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Store both samples and exemplars in the same timeseries buffer to remove the alloc when building final request, keep sub-slices in separate buffers for re-use

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Condense sample/exemplar delivery tests to parameterized sub-tests

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Rename test methods for clarity now that they also handle exemplars

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Rename counter variable. Fix instances where metrics were not updated correctly

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Add exemplars to LoadWAL benchmark

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* last exemplars timestamp metric needs to convert value to seconds with
ms precision

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Process exemplar records in a separate go routine when loading the WAL.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address review comments related to clarifying comments and variable
names. Also refactor sample/exemplar to enqueue prompb types.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Regenerate types proto with comments, update protoc version again.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Put remote write of exemplars behind a feature flag.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address some of Ganesh's review comments.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Move exemplar remote write feature flag to a config file field.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address Bartek's review comments.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Don't allocate exemplar buffers in queue_manager if we're not going to
send exemplars over remote write.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Add ValidateExemplar function, validate exemplars when appending to head
and log them all to WAL before adding them to exemplar storage.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address more reivew comments from Ganesh.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Add exemplar total label length check.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address a few last review comments

Signed-off-by: Callum Styan <callumstyan@gmail.com>

Co-authored-by: Martin Disibio <mdisibio@gmail.com>
2021-05-06 13:53:52 -07:00

2.7 KiB

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Disabled Features 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.

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.

Expand environment variables in external labels

--enable-feature=expand-external-labels

Replace ${var} or $var in the external_labels 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.

## 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.

Exemplars Storage

--enable-feature=exemplar-storage

OpenMetrics introduces the ability for scrape targets to add exemplars to certain metrics. Exemplars are references to data outside of the MetricSet. A common use case are IDs of program traces.

Exemplar storage is implemented as a fixed size circular buffer that stores exemplars in memory for all series. Enabling this feature will enable the storage of exemplars scraped by Prometheus. The flag storage.exemplars.exemplars-limit can be used to control the size of circular buffer by # of exemplars. An exemplar with just a traceID=<jaeger-trace-id> uses roughly 100 bytes of memory via the in-memory exemplar storage. If the exemplar storage is enabled, we will also append the exemplars to WAL for local persistence (for WAL duration).