Custom PromQL Query function to fetch mimir results

[ska663]

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We need to write a custom query function to minimize/abstract the query complexities to user with simple custom query function.

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Instead of writing complex queries to to find anomaly, simple anomaly function should help users. (avg_over_time(notifier_alerts{product_id="telemetry"}[1h])-avg_over_time(notifier_alerts{product_id="telemetry"}[1d]))/stddev_over_time(notifier_alerts{product_id="telemetry"}[1d])>3

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e.g anomaly({avg_over_time(notifier_alerts{product_id="telemetry"}[1h])})

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[dimitarvdimitrov]

I'm not sure I fully understand the issue. Are you proposing adding the ability for operators to write arbitrary additional promQL functions OR to add anomaly as a promQL function in Mimir?

Either way I think Prometheus itself would be a better place to add support for this. I don't see custom promQL functions relating to the distributed nature of Mimir. In other words, if the additional promQL functions make sense for Prometheus, then they do for Mimir and vice-versa. It's easier and would benefit more people if this was added in prometheus and then trickled down the Mimir instead of patching Mimir with these changes.