[GPRD] Enable pg_wait_sampling in Production

Production Change

Change Summary

As defined in https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/14027 we want to roll out pg_wait_sampling to gprd.

The extension has been installed and tested in staging, this CR will propagate it to gprd.

Change Details

1. Services Impacted - ServiceRegistry ServicePostgres Database
2. Change Technician - @alexander-sosna
3. Change Reviewer - @rhenchen.gitlab
4. Time tracking - 2 hours
5. Downtime Component - None*.

Detailed steps for the change

Change Steps - steps to take to execute the change

Estimated Time to Complete (mins) - 90 minutes

General

• Set label changein-progress /label ~change::in-progress
• Verify #7606 (closed) was executed successfully, at least 7 days ago!
• Verify https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/14267 is solved

This delay between activating pg_stat_kcache and pg_wait_sampling is important to evaluate the performance impact of each extension may have separately.

Rollout new version of gitlab-patroni to activate maintenance logic

• Merge Add pg_wait_sampling_reset logic
• Bump version to roll out the new logic by merging, ...

gprd-pg12-patroni-registry (7010420003992814451)

• Create extension: gitlab-psql -c "CREATE EXTENSION pg_wait_sampling;" on the primary
• Verify: gitlab-psql -c "SELECT * FROM pg_extension;" shows extension pg_wait_sampling is installed
• gitlab-psql -c "ALTER SYSTEM SET pg_wait_sampling.profile_pid = false;"
• gitlab-psql -c "ALTER SYSTEM SET pg_wait_sampling.history_size = 5000;"
• Monitor cluster performance for 15 minutes before proceeding

Main gprd-patroni-main-pg12-2004 (6959847276950353765)

• Create extension: gitlab-psql -c "CREATE EXTENSION pg_wait_sampling;" on the primary
• Verify: gitlab-psql -c "SELECT * FROM pg_extension;" shows extension pg_wait_sampling is installed
• gitlab-psql -c "ALTER SYSTEM SET pg_wait_sampling.profile_pid = false;"
• gitlab-psql -c "ALTER SYSTEM SET pg_wait_sampling.history_size = 5000;"
• Monitor cluster performance for 15 minutes before proceeding

gprd-patroni-ci-pg12-2004 (6959847276950353765)

• Create extension: gitlab-psql -c "CREATE EXTENSION pg_wait_sampling;" on the primary
• Verify: gitlab-psql -c "SELECT * FROM pg_extension;" shows extension pg_wait_sampling is installed
• gitlab-psql -c "ALTER SYSTEM SET pg_wait_sampling.profile_pid = false;"
• gitlab-psql -c "ALTER SYSTEM SET pg_wait_sampling.history_size = 5000;"
• Monitor cluster performance for 15 minutes before proceeding

General

• Monitor the performance of ALL clusters for 30 minutes before proceeding
• 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) - 15 minutes

• gitlab-psql -c "DROP EXTENSION pg_wait_sampling;" on the primary and check again.
• Verify: gitlab-psql -c "SELECT * FROM pg_extension;" shows extension pg_wait_sampling is no longre installed
• Set label changeaborted /label ~change::aborted

Monitoring

Key metrics to observe

• Metric:
  • Global: patroni Service Apdex, patroni Service RPS - Requests per Second
  • Per node: SQL Transactions Pooled per Node
  • Location:
    • Main cluster: https://dashboards.gitlab.net/d/patroni-main/patroni-overview?orgId=1
    • CI cluster: https://dashboards.gitlab.net/d/patroni-ci-main/patroni-ci-overview?orgId=1
  • What changes to this metric should prompt a rollback: It is expected that the nodes which are upgrade don't serve the application for a short period of time. If these metrics do not recover after one node is upgraded the deployment needs to be stopped and the root cause investigated. If this problem can't be solved a rollback is performed.

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.
  • 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.