Sr MongoDB Performance Engineer

Role Descriptions:
Must Have Skills:

1. Expert in MongoDB
2. Strong experience in Performance tuning
3. Fluent in the aggregation framework indexing strategy and read/write/read-concern semantics.
4. Strong explain-plan and profiler-driven query optimization
5. WiredTiger internals: cache eviction checkpoints journal compression document-level concurrency.
6. Replication and sharding operations at scale including shard-key design trade-offs.
7. Scripting for automation - Python
8. Strong experience with tuning of specific clusters queries indexes and schemas
9. Good experience designing sharding strategy and shard keys; plans resharding and zone strategy
10. Strong experience operating and monitoring existing sharded clusters; runs balancer fixes hot chunks

Nice To Have Skills:

1. MongoDB certification
2. Kubernetes operator experience for stateful MongoDB; Infrastructure-as-Code (Terraform/Ansible).

Technical/Functional Skills:

MongoDB Performance Engineer to own the throughput latency scalability and operational reliability of MongoDB landscape. This is a hands-on database engineering role not an application-developer role.
The engineer is accountable for making MongoDB fast predictable and cost-efficient at scale.
Performance engineering (Primary)
Profile and optimize slow queries and aggregation pipelines using explain plans the database profiler and log analysis.
Design review and rationalize indexes (compound partial wildcard Time To Live (TTL) text geospatial) applying the Equality Sort Range (ESR) rule; eliminate unused and redundant indexes that inflate write cost and cache pressure.
Tune the WiredTiger storage engine: internal cache sizing eviction and checkpoint behavior compression and journaling balanced against filesystem cache.

Operations & reliability
Operate and scale sharded clusters: balancer management chunk/range distribution jumbo-chunk remediation and (on modern versions) resharding.
Own backup/restore and Point-In-Time Recovery (PITR) strategy plus rolling upgrades and patching with zero or minimal downtime.
Infrastructure OS & platform
Right-size EC2 instances and EBS volumes (Input/Output Operations Per Second (IOPS) and throughput provisioning); on Kubernetes own StatefulSet storage class resource requests/limits anti-affinity and cache sizing against container memory limits.

Partner with application teams on data modeling; review schema changes; publish standards runbooks and capacity guidance.