Top 100 Apache Cassandra Interview Questions for 5+ Years of Experience

Basic Cassandra Questions

1. What is Apache Cassandra, and how does it differ from traditional relational databases?
2. Explain the Cassandra architecture.
3. What are the core components of Cassandra?
4. How does Cassandra handle scaling horizontally?
5. What is the role of the Cassandra Coordinator node?
6. Explain the concept of data distribution in Cassandra.
7. What is a node in Cassandra, and how does it work?
8. What is the Cassandra cluster, and how is it structured?
9. How does Cassandra handle data replication?
10. What is the Gossip Protocol in Cassandra?

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Data Modeling in Cassandra

1. How do you model data in Cassandra for high write throughput?
2. What are Primary Keys and Clustering Keys in Cassandra, and how do they work?
3. Explain the concept of denormalization in Cassandra.
4. How do you decide when to add an index in Cassandra?
5. What are wide rows in Cassandra, and how do they impact performance?
6. How would you design a Cassandra schema for time-series data?
7. Explain the concept of compound keys in Cassandra.
8. How does Cassandra handle secondary indexes, and when should they be used?
9. What is a collection data type in Cassandra, and how is it used?
10. How do you model multi-tenancy in Cassandra?

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Advanced Cassandra Questions

1. What is data consistency in Cassandra, and how is it achieved?
2. What are consistency levels in Cassandra, and when would you use each level?
3. How does Cassandra ensure eventual consistency?
4. What are tunable consistency levels, and how do they work?
5. How does Cassandra handle conflicts during replication?
6. What is quorum in Cassandra, and how does it affect consistency?
7. What is the write path and read path in Cassandra?
8. How does Cassandra handle CAP Theorem (Consistency, Availability, Partition Tolerance)?
9. What is hinted handoff in Cassandra?
10. What are compaction strategies in Cassandra, and why are they important?

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Performance Tuning and Optimization

1. How do you optimize write performance in Cassandra?
2. How do you optimize read performance in Cassandra?
3. What are memtables, and how do they impact performance?
4. Explain the concept of SSTables in Cassandra.
5. How does Cassandra handle tombstones and how does it impact performance?
6. What is compression in Cassandra, and how does it improve performance?
7. What are compaction and GC in Cassandra, and how do they affect performance?
8. How does Cassandra handle hot spots in a cluster?
9. How do you avoid disk I/O bottlenecks in Cassandra?
10. How do you deal with large write-heavy workloads in Cassandra?

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Replication, Clustering, and High Availability

1. How does Cassandra replication work across multiple data centers?
2. What are the different replication strategies in Cassandra?
3. What is NetworkTopologyStrategy, and how does it differ from SimpleStrategy?
4. How do you handle data consistency in multi-data center Cassandra clusters?
5. Explain the concept of RF (Replication Factor) in Cassandra.
6. How does Cassandra ensure fault tolerance across nodes and data centers?
7. What is replica placement, and how does it impact performance?
8. How do you manage data center awareness in Cassandra?
9. How do you handle node failures and repair in Cassandra?
10. What is the role of the hinted handoff mechanism in replication?

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Data Consistency and Clustering

1. How does Cassandra handle distributed transactions?
2. What is eventual consistency and how does Cassandra ensure it?
3. How does Cassandra handle read/write consistency?
4. What is the role of read repair in maintaining consistency?
5. How does Cassandra use Bloom Filters for faster lookups?
6. How does Cassandra handle heavy reads in a system?
7. How does Cassandra handle isolation levels?
8. What are tunable consistency levels, and how are they configured in Cassandra?
9. How do you configure and use Cassandra’s CL (Consistency Level) settings?
10. How does Cassandra handle inconsistencies between nodes?

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Maintenance and Monitoring

1. How do you monitor a Cassandra cluster in production?
2. What are the key metrics you should monitor in Cassandra?
3. How do you handle node repair in Cassandra?
4. What is the nodetool utility, and what are its common use cases?
5. How do you perform a rolling upgrade of a Cassandra cluster?
6. What is bootstrap node in Cassandra?
7. How do you monitor Cassandra performance and troubleshoot issues?
8. How do you identify and troubleshoot timeouts in Cassandra?
9. How do you manage disk usage and compaction in Cassandra?
10. How do you manage Cassandra backups and restore?

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Security and Authentication

1. How does Cassandra handle authentication and authorization?
2. What are Cassandra roles and how are they used for security?
3. How do you implement SSL encryption in Cassandra?
4. How do you manage audit logging in Cassandra?
5. What is Client-to-node encryption in Cassandra, and how does it work?
6. How does Cassandra handle LDAP authentication?
7. How do you protect data at rest in Cassandra?
8. How would you secure access to your Cassandra cluster?
9. How do you handle row-level access control in Cassandra?
10. How does Cassandra's internal security differ from other NoSQL databases?

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Advanced Features and Use Cases

1. What are Cassandra triggers, and how do they work?
2. How do you implement secondary indexes in Cassandra and what are their limitations?
3. What is Lightweight Transactions in Cassandra, and when should you use it?
4. Explain the concept of materialized views in Cassandra.
5. How do you use Cassandra with Apache Spark for large-scale analytics?
6. What is Cassandra's integration with Apache Kafka and how is it used?
7. How would you implement change data capture (CDC) in Cassandra?
8. What are user-defined types (UDTs) in Cassandra, and when would you use them?
9. How do you handle schema changes in a running Cassandra cluster?
10. How does Cassandra handle time-series data?

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Troubleshooting and Failures

1. How do you troubleshoot node failures in Cassandra?
2. How do you recover from data corruption in Cassandra?
3. How do you handle high-latency queries in Cassandra?
4. How would you debug a slow query in Cassandra?
5. How do you perform replica synchronization after a network partition?
6. How do you handle data drift in distributed Cassandra clusters?
7. How would you resolve write-timeout errors in Cassandra?
8. How do you deal with Cassandra's disk space usage and prevent it from filling up?
9. How do you analyze GC pauses in Cassandra?
10. How do you manage repairing inconsistencies across nodes in Cassandra?

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