INC17837406446545

P2newai_assisted

users-db read replica lag exceeding 90s after migration

Assembled Context — bounded to last 30 minutes

Rolling logs

[users-db-migrations] applied migration 0047_add_index_users_email.sql

[users-db-replica-2] WARN replication lag 94s (threshold 30s)

[users-service] WARN stale read detected for user profile lookups

Recent commits

27fb08f chore(db): add index on users.email for lookup perf — a.chen

Similar past incidents

(none found)

Diagnosis Agent

ran in parallel

Applying the database migration 0047_add_index_users_email.sql to add an index on the users.email column caused a substantial replication lag on the read replica users-db-replica-2, which in turn resulted in stale reads for user profile lookups in the users-service.

[users-db-migrations] applied migration 0047_add_index_users_email.sql
[users-db-replica-2] WARN replication lag 94s (threshold 30s)
[users-service] WARN stale read detected for user profile lookups

Assessed: P2 / database

Self-reported confidence: 95% (audit-only — not used by the gate)

gemini-flash-latest · 7988ms

Severity / Routing Agent

ran in parallel

P2 / database

Routed to: database-reliability-engineering

The replication lag is causing stale reads in the users-service, directly impacting user experience for profile lookups. While not a total outage (P1), it is a significant performance degradation following a schema change that requires immediate remediation by the database team.

Self-reported confidence: 95% (audit-only — not used by the gate)

gemini-flash-lite-latest · 1025ms

Scenario Matcher

deterministic, pre-LLM

Replica lag after schema migration

Replica lag following a schema migration requires a DBA to assess migration impact before any automated action; do not act automatically.

Match score: 90% · Recommended action: escalate_to_human

Matched tags: replica lag, migration, replication

Confidence Gate

Pending…