Sharding

A collection has a 'status' field with only three possible values: 'active', 'pending', and 'closed'. Why is 'status' a poor choice for a shard key by itself?

A financial services company runs a sharded MongoDB cluster with three shards. They need to shard a new collection that stores transaction records. The collection will be queried primarily by 'accountId' and 'transactionDate'. The team wants to minimize scatter-gather queries and ensure even data distribution. Which two actions should they take when choosing and implementing the shard key? (Choose two.)

An organization wants to restrict customer data for European Union residents to a specific set of physical servers located in Frankfurt, complying with data residency regulations. Which MongoDB sharding feature should the DBA implement to achieve this?

A MongoDB DBA is configuring a new sharded cluster. The application requires that queries on the sharded collection include the shard key to avoid scatter-gather. The DBA decides to use a ranged shard key on the field 'region'. After sharding, the DBA notices that queries filtering only on 'region' are performing well, but queries that also filter on 'city' are still scanning all shards. What is the most likely cause?

A production MongoDB 6.0 sharded cluster has a collection with a ranged shard key on the field `customerId`. Over time, the team notices that nearly all new documents have monotonically increasing `customerId` values, and one shard is receiving a disproportionate share of writes while the other shards remain relatively idle. The balancer is enabled and running. Which of the following is the most likely explanation for this imbalance?

An administrator needs to distribute a high-throughput collection evenly across a sharded cluster using a hashed shard key. What is the primary characteristic of MongoDB's hashed sharding strategy that makes it effective for preventing write bottlenecks?

A sharded cluster has a three-member replica set for its config servers. If two of the three config servers go offline, what is the immediate impact on the cluster's operations?

An application executes a query on a sharded collection that does not include the shard key. What is the impact on the cluster performance?

Refer to the exhibit. An administrator inspects chunk metadata for a sharded collection using a compound shard key: { region: 1, account_id: 1 }. What does the presence of MinKey and MaxKey signify in this specific chunk range definition?

A MongoDB 6.0 sharded cluster has a collection sharded with a hashed shard key on 'userId'. The operations team needs to run an aggregation that groups documents by 'userId' and calculates the total transaction amount. They want to know whether the aggregation can be optimized to run only on the shards that contain the relevant 'userId' values. Which statement describes the correct behavior?

When is it appropriate to use a hashed shard key instead of a ranged shard key in a MongoDB sharded collection?

A sharded cluster has a collection sharded on `{ location: 1 }`. A query is executed with the filter `{ location: { $in: ["NY", "CA"] } }`. How does MongoDB route this query?

When designing a compound shard key in MongoDB, what is the architectural significance of placing a high-cardinality field as the prefix compared to placing a low-cardinality field first?

A DBA is troubleshooting a sharded cluster where the balancer is not migrating chunks even though there is an imbalance. The DBA runs `sh.getBalancerState()` and it returns `true`. Which of the following is the most likely reason the balancer is not migrating chunks?

Which TWO of the following are primary benefits of implementing sharding in a MongoDB environment?

A multi-document transaction is being executed across multiple shards. Which component is responsible for coordinating the transaction and ensuring the all-or-nothing property?

A DBA needs to ensure that chunk migrations only occur during a specific maintenance window from 02:00 to 04:00. Which configuration change is required?

Which THREE components are required to form a functional MongoDB sharded cluster?

A MongoDB 6.0 sharded cluster has a collection with a ranged shard key on the field 'customerId'. The balancer has been running normally, but the operations team notices that one shard consistently holds significantly more chunks than the others. They want to understand which internal metadata collection the mongos uses to determine chunk distribution and to verify the current chunk-to-shard mapping. Which collection should they query?

An administrator notices that the balancer in a MongoDB sharded cluster is repeatedly migrating chunks between two shards, causing performance degradation. The administrator wants to temporarily stop the balancer to investigate. Which command should be used on mongos?

A developer chooses Hashed Sharding for a collection. What is a significant limitation of this sharding strategy compared to Ranged Sharding?

An engineering team must shard a high-volume collection tracking global financial transactions. The chosen shard key is based on a timestamp field containing the exact millisecond of each transaction. Why will this specific shard key choice severely degrade cluster write performance over time?

A DBA is preparing to shard a collection in a MongoDB 6.0 cluster. The collection currently has no indexes other than the default _id index. The chosen shard key is { userId: 1 }. What must the DBA do before running shardCollection?

Which TWO statements accurately describe the behavior and management of orphaned documents in a MongoDB sharded cluster? Choose 2 answers.

A MongoDB 6.0 sharded cluster uses a shard key of { region: 1, customerId: 1 } for a global order collection. Most queries filter on customerId only, without region. The operations team observes that nearly every read is a scatter-gather across all shards. What is the most accurate explanation for this behavior?

An administrator notices that the MongoDB balancer is actively migrating chunks during peak business hours, causing noticeable application latency spikes. What is the standard administrative approach to mitigate this performance impact?

During routine cluster maintenance, an administrator needs to remove an underperforming shard from a production MongoDB sharded cluster safely. What is the mandatory first step the administrator must execute?

An application issues a find query against a sharded collection without including the shard key in the query filter. How does the mongos query router handle this operation?

Refer to the exhibit. An administrator attempts to execute the shardCollection command but receives the displayed error message. What is the root cause of this failure?

An application serves users in Europe and North America. The DBA wants to ensure that European user data stays on shards located in Europe to comply with data residency laws. Which feature should be used?

An application requires high write throughput for time-series data indexed by a timestamp field. You observe that all incoming data is being routed to a single shard, creating a write hotspot. Which shard key strategy best resolves this performance bottleneck?

A MongoDB sharded cluster has a collection with a hashed shard key on the field 'userId'. A query is executed that includes an equality condition on userId. How does mongos route this query?

A company stores IoT sensor data with a high ingestion rate. They use a monotonically increasing timestamp as the shard key. What is the most likely performance bottleneck for this cluster?

A database administrator is setting up a new sharded cluster and needs to enable sharding on a database named 'sales' before sharding any collections. Which command should be executed on mongos to enable sharding for this database?

A financial services company shards a transactions collection using a ranged shard key on an incrementing timestamp field. Over several months, the cluster develops a single hot shard that receives almost all writes, while the other shards remain nearly idle. Which change best addresses the root cause while preserving efficient range queries on timestamp?

Which THREE components are mandatory architectural parts of every fully functioning MongoDB sharded cluster deployment? Choose 3 answers.

A MongoDB DBA is managing a sharded cluster where the collection 'orders' is sharded on the field 'orderDate' using ranged sharding. The DBA needs to add a new shard to the cluster to handle increasing data volume. After adding the shard, the balancer begins migrating chunks. During this migration, the DBA runs a query that includes 'orderDate' and notices increased latency. What is the most likely reason for the increased latency?