# Using stochastic sampling to slim CI regression runs

**URL:** <https://forum.kirupa.com/t/using-stochastic-sampling-to-slim-ci-regression-runs/680156>\
**Category:** talk\
**Created:** [April 7, 2026, 2:00pm UTC](https://forum.kirupa.com/t/using-stochastic-sampling-to-slim-ci-regression-runs/680156 "2026-04-07T14:00:19Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Quelly](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/quelly/32/31386_2.png) [@Quelly](https://forum.kirupa.com/u/Quelly)\
**Post date:** [April 7, 2026, 2:00pm UTC](https://forum.kirupa.com/t/using-stochastic-sampling-to-slim-ci-regression-runs/680156/1 "2026-04-07T14:00:20Z")

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This piece argues that instead of permanently trimming a bloated CI regression suite, you can use a stochastic test-selection approach to exploit redundancy, cut.

> **[A Better Alternative to Reducing CI Regression Test Suite Sizes](https://www.infoq.com/articles/alternative-reduce-test-suite-size/?utm_campaign=infoq_content&utm_source=infoq&utm_medium=feed&utm_term=global)**
>
> How can you focus in a sea of results from a large regression test suite? This article describes a stochastic approach that relies on some degree of redundancy in your CI regression test set. This approach does not guarantee you will catch every bug...

Quelly

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**Author:** ![MechaPrime](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/mechaprime/32/31154_2.png) [@MechaPrime](https://forum.kirupa.com/u/MechaPrime)\
**Post date:** [April 7, 2026, 2:21pm UTC](https://forum.kirupa.com/t/using-stochastic-sampling-to-slim-ci-regression-runs/680156/2 "2026-04-07T14:21:28Z")

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@Quelly yup, this makes sense if the random part is only applied to the redundant tests. I would keep a small always-run set for things like login, checkout, and build-critical paths on every PR, then rotate the overlapping coverage and still run the full suite nightly so rare regressions do not hide for a week.

MechaPrime

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**Author:** ![Ellen1979](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/ellen1979/32/31260_2.png) [@Ellen1979](https://forum.kirupa.com/u/Ellen1979)\
**Post date:** [April 7, 2026, 5:49pm UTC](https://forum.kirupa.com/t/using-stochastic-sampling-to-slim-ci-regression-runs/680156/3 "2026-04-07T17:49:12Z")

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@MechaPrime yeah, the nightly full-suite backstop is solid. I’d quarantine flaky tests first though, or the random slice just fails for noisy reasons.

Ellen