# Flagsmith: Critical incident: Core API is not responding

**Summary:** _summary pending_
- Kind: Major incident · Label: critical (vendor)
- Changed: 2023-09-05 12:01 UTC · Detected: 2026-10-19 18:33 UTC
- [Source: https://stspg.io/7ff3xz5flqbw](https://stspg.io/7ff3xz5flqbw)
- [Company: Flagsmith](https://rewindex.com/company/flagsmith.md)
- Versions: before (none: first archived) → after incident\_version:734/h64tzjy7btly@06788c8f8b48
- Change 1 of 1 for this incident

Incident page (full timeline): [Core API is not responding](https://rewindex.com/company/flagsmith/incidents/h64tzjy7btly.md)
## What changed

**1. Added: Title**

```diff
+ Core API is not responding
```

**2. Added: Impact**

```diff
+ critical
```

**3. Added: Status**

```diff
+ postmortem
```

**4. Added: Start time**

```diff
+ 2023-09-05 12:01 UTC
```

**5. Added: Resolved time**

```diff
+ 2023-09-05 12:01 UTC
```

**6. Added: Affected components**

```diff
+ Admin API, Core API
```

**7. Added: Update** (investigating) · 2023-09-05 09:45 UTC

```diff
+ We are currently investigating this issue.
```

**8. Added: Update** (identified) · 2023-09-05 09:51 UTC

```diff
+ We have identified a database migration that has failed as part of a new release. We are working to re-apply the migration.
```

**9. Added: Update** (monitoring) · 2023-09-05 10:25 UTC

```diff
+ A fix has been implemented and we are monitoring the results.
```

**10. Added: Update** (monitoring) · 2023-09-05 10:25 UTC

```diff
+ We are continuing to monitor for any further issues.
```

**11. Added: Update** (resolved) · 2023-09-05 12:01 UTC

```diff
+ This incident has been resolved. A postmortem will follow.
```

**12. Added: Update** (postmortem) · 2023-09-12 16:50 UTC

```diff
+ **Summary** On September 5th at 09:45 UTC, we initiated a release that included a database migration aimed at introducing a new constraint to the table containing information related to flags. According to our pre-live tests, this task should not have taken more than 50 milliseconds. Unfortunately, during the release to production, due to the high throughput on a particular table that it needed to acquire a temporary lock on, this caused a backlog of blocked connections waiting on the migration to complete. This caused a knock on effect that exhausted the connections on the database and a full restart was necessary. Once the restart was complete, the connections were restored and service was resumed. This happened at 10:20 UTC. **Next Steps** We have researched the cause of the issue and we do still have further research to understand certain aspects. Our current plan in the meantime is to implement certain safeguards as can be found in the following links to the Postgres documentation which should help reduce any impact in the future. [https://www.postgresql.org/docs/11/runtime-config-client.html](https://www.postgresql.org/docs/11/runtime-config-client.html)  [https://www.postgresql.org/docs/11/runtime-config-logging.html](https://www.postgresql.org/docs/11/runtime-config-logging.html) \(ʹlog_lock_waitsʹ\)
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2023-09-05 12:01 UTC | Critical incident: Core API is not responding (this change) | critical |

All Flagsmith changes: [timeline](https://rewindex.com/company/flagsmith/changes.md)
_Diff excerpts are shown on normalized text: dates, counters and tokens appear as ‹date›, ‹count›, ‹tok›; noise-only edits are hidden. Rewindex shows the changed passages, not a copy of the page._


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Canonical: https://rewindex.com/change/ic115460bc22d21 · Markdown: https://rewindex.com/change/ic115460bc22d21.md · JSON: https://rewindex.com/api/v1/changes/ic115460bc22d21 · Generated 2026-10-20T00:48:46.299Z