grafana/loki

Detailed Documentation around Result Caching

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#8,895 opened on Mar 24, 2023

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Description

We are trying to understand how the result caching works for metrics queries in Loki and there seems to be not detailed documentation around it.

We did some testing and below are our high-level observation but it would be good to know the expected behaviour so that we can take advantage of the results cache for long duration queries.

  • d1,d2,d3,d4,d5,d6,d7 - queried individualy but tried to query between d1 to d7 it is not using the cache
  • We need to build the cache like d1,d1+d2,d1+d2+d3,d1+d2+d3+d4,d1+d2+d3+d4+d5,d1+d2+d3+d4+d5+d6,d1+d2+d3+d4+d5+d6+d7 and then it works
  1. Detailed documentation of how results query works and best practice around logql to use caching effectively will be helpful
  2. Also logging to indicate if the query is using the cache (full or partial or not using) will be good information to expose.

Contributor guide

Research direction
Review existing caching documentation and source code to explain how metric query result caching works in Loki. Provide best practices for effective use and suggest logging improvements to indicate cache usage.
Tech stack
go
Domain
backend
Issue type
Documentation
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
1
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
understanding of Loki and query caching concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
85