# Missing index after migration: first 30 minutes checklist

Source: https://releasefailures.com/incidents/missing-index-after-migration/
Content version: 1.0.0
Verified on: 2026-10-21
Licence: CC BY 4.0

Definition: A migration drops or forgets an index and query latency rises under production load.
- [ ] FM-01 Compare the index list on the slow table with the list from before the migration.
- [ ] FM-02 Check whether any index on that table is marked INVALID.
- [ ] FM-03 Stop the progressive rollout of the migration to the remaining regions or shards.
- [ ] FM-04 Pause analytics queries and other non-essential workloads on the table before rebuilding the index.
- [ ] FM-05 Decide whether to rebuild the index now or after peak traffic, because a rebuild under load can overload the database cluster.
- [ ] FM-06 Recreate the index shard by shard, and on shards under heavy load revoke application reads and writes on the table during the build.
- [ ] FM-07 Publish a status note listing the slow or failing features, such as API timeouts or delayed background jobs.