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