2025-08-21: [gstg] Reindex all zoekt shards

Production Change

Change Summary

Reindex all zoekt shards in staging. This is part of the traversal IDs optimization: gitlab-org&17589 (closed).

There was previously a bug gitlab-org/gitlab#560536 (closed), and we want to trigger reindexing again to make sure it is a smooth process before rolling out to production.

We attempted to do this previously, but ran into issue with "stuck" tasks #20353 (closed). We expect this attempt to go successfully.

Change Details

1. Services Impacted - ServiceZoekt
2. Change Technician - @johnmason
3. Change Reviewer - @dgruzd @rkumar555
4. Scheduled Date and Time (UTC in format YYYY-MM-DD HH:MM) - 2025-08-21 11:30 UTC
5. Time tracking - 1 day
6. Downtime Component - This is zero downtime reindexing

Set Maintenance Mode in GitLab

If your change involves scheduled maintenance, add a step to set and unset maintenance mode per our runbooks. This will make sure SLA calculations adjust for the maintenance period.

Detailed steps for the change

Pre-execution steps

• Make sure all tasks in Change Technician checklist are done
• 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.)
  • The SRE on-call provided approval with the eoc_approved label on the issue.
• For C1, C2, or blocks deployments change issues, Release managers have been informed 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.

Change steps - steps to take to execute the change

Estimated Time to Complete (mins) - 30m

• Set label changein-progress /label ~change::in-progress
• Set all zoekt repositories to have a schema version of 0.

  Search::Zoekt::Repository.update_all(schema_version: 0)

• Ensure zoekt_index_empty_repos is enabled

  Feauture.enable :zoekt_index_empty_repos

• Unpause zoekt indexing: Gitlab::CurrentSettings.update!(zoekt_indexing_paused: false)
• Monitor and ensure all repositories eventually have their schema version upgraded back to 2531:

  Search::Zoekt::Repository.group(:schema_version).count

• 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) - 1m

• Search::Zoekt::Repository.update_all(schema_version: 2531)
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

Number of zoekt tasks:

Search::Zoekt::Task.group(:state).count

Number of zoekt repositories upgraded to 2531:

Search::Zoekt::Repository.group(:schema_version).count

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 change window has been agreed with Release Managers in advance of the change. If the change is planned for APAC hours, this issue has an agreed pre-change approval.
  • The labels blocks deployments and/or blocks feature-flags are applied as necessary.

Change Technician checklist

• 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 Infrastructure Manager provided approval with the manager_approved label on the issue. Mention @gitlab-org/saas-platforms/inframanagers in this issue to request approval and provide visibility to all infrastructure managers.
• For C1, C2, or blocks deployments change issues, confirm with Release managers that the change does not overlap or hinder any release process (In #production channel, mention @release-managers and this issue and await their acknowledgment.)