[GPRD] Complete ci_builds partitioning - 2nd attempt

Production Change

Change Summary

This is the second manual attempt to attaching ci_builds as a partition to p_ci_builds since the first one failed to get the locks: #14072 (closed)

We learned from the first attempt that regular autovacuum processes while they are interruptible it takes 5 seconds for postgres to interrupt them and that's too expensive for our timeout budget.

This uses the same SQL from the previous attempt, but now it's executed with a database helper from the Rails console to retry the execution automatically.

Change Details

  1. Services Impacted - ServicePostgres
  2. Change Technician - DRI for the execution of this change
  3. Change Reviewer - DRI for the review of this change
  4. Time tracking - 35 minutes
  5. Downtime Component - No downtime

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 30 minutes

  • At t-3h pause the pipelines primary key background migration by running /chatops run batched_background_migrations pause 247 --database ci in the #production Slack channel
  • Set label changein-progress /label ~change::in-progress
  • Open a Rails console with write access
  • Enable the feature flag for the service with Feature.enable(:attach_ci_builds_partition)
  • Attach ci_builds as a partition to p_ci_builds with:
Gitlab::Database::CiBuildsPartitioning.new(logger: Gitlab::JsonLogger.new($stdout)).execute
  • Re-enable the migration with /chatops run batched_background_migrations resume 247 --database ci
  • Disable the feature flag: Feature.disable(:attach_ci_builds_partition)
  • Set label changecomplete /label ~change::complete

Rollback

Rollback steps - steps to be taken in the event of a need to rollback this change

Estimated Time to Complete (mins) - 5 minutes

  • Disable the feature flag: Feature.disable(:attach_ci_builds_partition)
  • Enable the background migration /chatops run batched_background_migrations resume 247 --database ci
  • Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

Change Reviewer checklist

C4 C3 C2 C1:

  • Check if the following applies:
    • The scheduled day and time of execution of the change is appropriate.
    • The change plan is technically accurate.
    • The change plan includes estimated timing values based on previous testing.
    • The change plan includes a viable rollback plan.
    • The specified metrics/monitoring dashboards provide sufficient visibility for the change.

C2 C1:

  • Check if the following applies:
    • The complexity of the plan is appropriate for the corresponding risk of the change. (i.e. the plan contains clear details).
    • The change plan includes success measures for all steps/milestones during the execution.
    • The change adequately minimizes risk within the environment/service.
    • The performance implications of executing the change are well-understood and documented.
    • The specified metrics/monitoring dashboards provide sufficient visibility for the change.
      • If not, is it possible (or necessary) to make changes to observability platforms for added visibility?
    • The change has a primary and secondary SRE with knowledge of the details available during the change window.
    • The labels blocks deployments and/or blocks feature-flags are applied as necessary

Change Technician checklist

  • Check if all items below are complete:
    • The change plan is technically accurate.
    • This Change Issue is linked to the appropriate Issue and/or Epic
    • Change has been tested in staging and results noted in a comment on this issue.
    • A dry-run has been conducted and results noted in a comment on this issue.
    • The change execution window respects the Production Change Lock periods.
    • For C1 and C2 change issues, the change event is added to the GitLab Production calendar.
    • For C1 and C2 change issues, the SRE on-call has been informed prior to change being rolled out. (In #production channel, mention @sre-oncall and this issue and await their acknowledgement.)
    • For C1 and C2 change issues, the SRE on-call provided approval with the eoc_approved label on the issue.
    • For C1 and C2 change issues, the Infrastructure Manager provided approval with the manager_approved label on the issue.
    • Release managers have been informed (If needed! Cases include DB change) prior to change being rolled out. (In #production channel, mention @release-managers and this issue and await their acknowledgment.)
    • There are currently no active incidents that are severity1 or severity2
    • If the change involves doing maintenance on a database host, an appropriate silence targeting the host(s) should be added for the duration of the change.
Edited by Marius Bobin