PromQL Data Selection Explained | Selectors, Lookback Delta, Offsets, and Absolute "@" Timestamps

In this video, I explain how Prometheus / PromQL data selection works in detail. I go into instant and range vector selectors, label matchers, the 5-minute lookback delta for instant vector selectors, staleness markers and staleness handling, and then explain relative offsets and absolute "@" timestamps for selectors.
Check out my Prometheus training courses if you want to learn Prometheus in a structured way from the ground up:
training.promlabs.com/
The Prometheus blog post about the "@" modifier, as mentioned in the video:
prometheus.io/blog/2021/02/18...
Chapters:
00:00 Introduction
00:49 Instant Vector Selectors
02:54 Label Matchers
04:32 Visualizing Instant Vector Selector Behavior (Lookback Delta)
06:01 Staleness Markers and Staleness Handling
07:33 Range Vector Selectors
08:56 Visualizing Range Vector Selector Behavior
09:26 Relative Offsets ("offset" Modifier)
10:02 Visualizing Offsets for Instant Vector Selectors
10:28 Offset Use Cases
11:07 Visualizing Offsets for Range Vector Selectors
11:17 Absolute Evaluation Timestamps ("@" modifier)
12:18 Visualizing Absolute Evaluation Timestamps
12:53 Syntactic Order for Modifiers
13:34 Outro & PromLabs Trainings
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[@C1rcu17]

This video is so underrated!

[@harshavardhangupta7325]

Super video. Thank you so much. Please make more videos. This channel is the only main source for Prometheus videos.

[@alexr6631]

Awesome! Everything is clear!

[@tejaswinivadlamudi1372]

Thank you for delivering such a clear and precise presentation!

[@bsatrialsguy9095]

Thanks ..
Good to see you again ..

[@Jam-ht2ky]

Your videos are blessing!

[@Vaisakhreghu007]

Gute Arbeit !

[@vijaygharge2414]

Awesome 👏

[@stefand.9555]

Great video with excellent explanations. Many thanks.
Nevertheless, I am still wondering if the following use case is possible:
Query for metrics of each month in the same year. Which means that the range is not fix but changes depending on the year (applies only to February). The timestamp must be calculated (e.g. the timestamp is 1. of January of same year)
The idea behind is to see a usage for each month.
Is there a way to query that?

[@mannycardenas4613]

How do I select data by month?

[@CelineLeMenn]

the "@" modifier does not work anymore !

[@PromLabs]

It still does! Maybe you are using a Prometheus version which is very old which doesn't support it yet?

[@georgejames3868]

Hey arnold schwarzenegger is that you?