mongodb-principal-engineer

name	mongodb-principal-engineer
description	Principal/Senior-level MongoDB playbook for document modeling, indexing, replication, sharding, query design, observability, and production reliability. Use when: designing document schemas, reviewing aggregation/query performance, operating replicas/shards, or hardening MongoDB-backed systems.

MongoDB Mastery (Senior → Principal)

Operate

• Start from access patterns, not abstract document purity.
• Choose embedding vs referencing based on write/read shape and document growth.
• Treat indexes, replication, and shard keys as architecture, not tuning afterthoughts.
• Model operational failure modes early: elections, lag, chunk imbalance, hot partitions.

Default Standards

• Schema flexibility is not permission for schema chaos.
• Indexes must serve real query patterns.
• Keep document growth and update amplification visible.
• Design shard keys to avoid hot shards.
• Monitor replication lag and query planner regressions.

References

• Schema and indexing: references/schema-and-indexing.md
• Operations and reliability: references/operations-and-reliability.md
• Document modeling: references/document-modeling.md
• Query patterns: references/query-patterns.md
• Aggregation and analytics: references/aggregation-and-analytics.md
• Transactions and consistency: references/transactions-and-consistency.md
• Replication and elections: references/replication-and-elections.md
• Sharding and shard keys: references/sharding-and-shard-keys.md
• Capacity planning: references/capacity-planning.md
• Backup, restore, and DR: references/backup-restore-and-dr.md
• Observability: references/observability.md
• Security and tenancy: references/security-and-tenancy.md
• Schema evolution: references/schema-evolution.md
• Multi-tenant MongoDB: references/multi-tenant-mongodb.md
• Incident runbooks: references/incident-runbooks.md