## Summary Roll out [the feature](https://gitlab.com/gitlab-org/gitlab/-/issues/536042) currently behind the `incremental_database_health_defer_delay` feature flag. - DRI: @imanpalsingh - Team Slack channel: `#g_database_architecture` > [!note] > > Process and guidance live in the docs — this issue is just the commands and a place to track the rollout. "Rolling out" means incrementally enabling the flag on GitLab.com to validate stability — it is not the same as releasing the feature, which happens when the flag is removed. [Feature flag controls](https://docs.gitlab.com/development/feature_flags/controls/) · [Feature flag lifecycle](https://handbook.gitlab.com/handbook/product-development/how-we-work/product-development-flow/feature-flag-lifecycle/#feature-flag-lifecycle) ## What could go wrong? The flag adds exponential backoff (doubling from the worker's `delay_by`, capped at 30 minutes, plus up to 10% jitter) to the re-enqueue delay of Sidekiq jobs deferred by `defer_on_database_health_signal`. Roughly 185 low-urgency workers are opted in. - Jobs can sleep up to 30 minutes past database recovery (by design, bounded by the cap). Watch completion latency of opted-in workers after long stop signals. - `Feature.current_request` is a fresh actor per Sidekiq execution, and every deferral is a new execution, so at intermediate percentages a single job's consecutive deferrals blend backoff and flat delay. Metrics are clearest at 0% and 100%; plan to move through intermediate percentages quickly. - Rollback is instant: disabling the flag restores the flat `delay_by` on the next deferral. No job payload changes are involved (`deferred_count` already exists on all deferred jobs). Dashboards to watch on https://dashboards.gitlab.net: - `sidekiq_jobs_skipped_total{action="deferred", reason="database_health_check"}` rate per worker (feeds the `SidekiqJobsDeferredByDBHealthCheck` alert; the deferral rate should drop during stop signals) - Redis Sidekiq scheduled set size and memory saturation ## Rollout Run all production `/chatops` in [`#production`](https://gitlab.slack.com/archives/C101F3796) and cross-post the results to `#g_database_architecture`. Background: [incremental rollout process](https://docs.gitlab.com/development/feature_flags/controls/#process), [feature actors](https://docs.gitlab.com/development/feature_flags/#feature-actors). **Non-production** ``` /chatops gitlab run feature set incremental_database_health_defer_delay 50 --actors --dev --pre --staging --staging-ref /chatops gitlab run feature set incremental_database_health_defer_delay true --dev --pre --staging --staging-ref ``` **Production** — percentage rollout (wait ≥15 min between steps, watch dashboards): ``` /chatops gitlab run feature set incremental_database_health_defer_delay <percentage> --actors ``` Or target specific actors instead: ``` /chatops gitlab run feature set --project=gitlab-org/gitlab,gitlab-org/gitlab-foss incremental_database_health_defer_delay true /chatops gitlab run feature set --group=gitlab-org,gitlab-com incremental_database_health_defer_delay true /chatops gitlab run feature set --user=imanpalsingh incremental_database_health_defer_delay true ``` ## Before global rollout Confirm the relevant gotchas before going to 100% — see [enabling a feature for GitLab.com](https://docs.gitlab.com/development/feature_flags/controls/#enabling-a-feature-for-gitlabcom): - [Docs + version history](https://docs.gitlab.com/development/documentation/feature_flags/) updated - [Breaking changes](https://docs.gitlab.com/development/documentation/release_notes/#deprecations-removals-and-breaking-changes) announced, if any - [Change management issue](https://handbook.gitlab.com/handbook/engineering/infrastructure-platforms/change-management/#feature-flags-and-the-change-management-process) opened, if required - [External API consumers](https://docs.gitlab.com/development/feature_flags/#do-not-use-feature-flags-in-external-api-consumers) handled with a fail-open mechanism, if applicable ## Cleanup Remove the flag once [deemed stable](https://handbook.gitlab.com/handbook/product-development/how-we-work/product-development-flow/feature-flag-lifecycle/#feature-flag-lifecycle) — see [cleaning up](https://docs.gitlab.com/development/feature_flags/controls/#cleaning-up). Track it here, or open a follow-up [Feature Flag Cleanup issue](https://gitlab.com/gitlab-org/gitlab/-/issues/new?description_template=Feature%20Flag%20Cleanup). Remove the flag and its YAML definition from the codebase, then: ``` /chatops gitlab run release check <merge-request-url> 19.3 /chatops gitlab run feature delete incremental_database_health_defer_delay --dev --pre --staging --staging-ref --production ``` ## Rollback ``` /chatops gitlab run feature set incremental_database_health_defer_delay false # production /chatops gitlab run feature set incremental_database_health_defer_delay false --dev --pre --staging --staging-ref # non-production /chatops gitlab run feature delete incremental_database_health_defer_delay --dev --pre --staging --staging-ref --production # remove entirely ```