2021-08-10: Postgres transactions showing high rate of statement timeouts

Current Status

For approximately 15 minutes there was a Patroni apdex drop that caused errors, statement timeouts, delayed Job processing and slow responses for all GitLab services.

This incident appears to be a repeat of https://gitlab.com/gitlab-com/gl-infra/production/-/issues/5306 . All occurrences of this issue have happened around the time of a deploy. See https://gitlab.com/gitlab-org/gitlab/-/issues/336788#note_646251192 for an explanation of the previous incident. More details will follow in https://gitlab.com/gitlab-com/ops-sub-department/ops-engineering-management/-/issues/13

Summary for CMOC notice / Exec summary:

1. Customer Impact: All services
2. Customer Impact Duration: 09:38 UTC - Most services recovered 09:53 UTC (15 minutes duration ), we had some lingering effect on ci jobs queue up to 10:04 UTC
3. Current state: See Incident::<state> label
4. Root cause: TBD

Timeline

View recent production deployment and configuration events / gcp events (internal only)

All times UTC.

2021-08-10

• 09:36 - Apdex for Patroni starts to degrade
• 09:52 - status.io communication started
• 09:44 - ahmad declares incident in Slack.
• 09:55 - Apdex for Patroni recovers

Corrective Actions

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Incident Review

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Customer Impact

1. Who was impacted by this incident? (i.e. external customers, internal customers)
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2. What was the customer experience during the incident? (i.e. preventing them from doing X, incorrect display of Y, ...)
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3. How many customers were affected?
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4. If a precise customer impact number is unknown, what is the estimated impact (number and ratio of failed requests, amount of traffic drop, ...)?
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What were the root causes?

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Incident Response Analysis

1. How was the incident detected?
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2. How could detection time be improved?
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3. How was the root cause diagnosed?
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4. How could time to diagnosis be improved?
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5. How did we reach the point where we knew how to mitigate the impact?
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6. How could time to mitigation be improved?
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7. What went well?
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Post Incident Analysis

1. Did we have other events in the past with the same root cause?
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2. Do we have existing backlog items that would've prevented or greatly reduced the impact of this incident?
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3. Was this incident triggered by a change (deployment of code or change to infrastructure)? If yes, link the issue.
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Lessons Learned

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Guidelines

• Blameless RCA Guideline

Resources

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