100+ Free Apache Cassandra Developer Associate Practice Questions

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Question 1

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Which protocol does Cassandra use for nodes to exchange state and membership information about one another?

Raft

Two-phase commit

Paxos

Gossip

to track

2026 Statistics

Key Facts: Apache Cassandra Developer Associate Exam

Number of Questions

DataStax

70% (42/60)

Passing Score

DataStax

90 minutes

Time Limit

DataStax

$145 USD

Exam Fee (free voucher often available)

DataStax

DS201 + DS220

Recommended Learning Path

DataStax Academy

Online proctored

Delivery Format

DataStax

The DataStax Apache Cassandra Developer Associate exam has 60 questions in 90 minutes and requires 70% (42 of 60) to pass, for a $145 fee that is often waived by a free voucher after the Academy learning path. It is online proctored and aligns to DS201 (Foundations) and DS220 (Data Modeling). Coverage centers on query-first data modeling, partition and clustering keys, denormalization, CQL collections, UDTs, materialized views, and batches, plus Cassandra architecture and tunable consistency.

Sample Apache Cassandra Developer Associate Practice Questions

Try these sample questions to test your Apache Cassandra Developer Associate exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1In Apache Cassandra, which component determines which node in the ring is responsible for storing a given row?

A.The hash of the partition key produced by the partitioner

B.The clustering columns hashed against the token ranges

C.The replication factor set on the keyspace

D.The order in which the row was inserted

Explanation: Cassandra applies the partitioner (Murmur3Partitioner by default) to the partition key to produce a token. That token maps to a position on the ring, and the node owning that token range becomes the primary replica for the row. This is why partition-key design controls data placement.

2What is the default partitioner used by modern Apache Cassandra clusters?

A.RandomPartitioner

B.ByteOrderedPartitioner

C.Murmur3Partitioner

D.OrderPreservingPartitioner

Explanation: Murmur3Partitioner is the default in modern Cassandra. It uses the MurmurHash function to produce 64-bit tokens in the range -2^63 to +2^63-1, giving fast, uniform distribution of partitions across the ring.

3Which protocol does Cassandra use for nodes to exchange state and membership information about one another?

A.Gossip

B.Paxos

C.Raft

D.Two-phase commit

Explanation: Cassandra uses a peer-to-peer gossip protocol. Each node periodically exchanges state information about itself and other nodes it knows about, allowing the cluster to discover topology, detect failures, and converge on membership without any central master.

4What is the primary purpose of a snitch in a Cassandra cluster?

A.To compress SSTables before flushing them to disk

B.To enforce the consistency level requested by the client

C.To inform Cassandra about the network topology so replicas are placed across racks and datacenters

D.To hash partition keys into tokens

Explanation: A snitch tells Cassandra which datacenter and rack each node belongs to. NetworkTopologyStrategy uses this information to place replicas on different racks and datacenters, improving fault tolerance and routing reads to the closest replicas.

5Which replication strategy is recommended for production clusters that may span multiple datacenters?

A.SimpleStrategy

B.EverywhereStrategy

C.LocalStrategy

D.NetworkTopologyStrategy

Explanation: NetworkTopologyStrategy lets you specify a replication factor per datacenter and places replicas on distinct racks using snitch information. It is the recommended strategy for production and any multi-datacenter deployment because it is rack- and DC-aware.

6When a node responsible for a write is temporarily down, what mechanism lets the coordinator store the write and deliver it later?

A.Read repair

B.Anti-entropy repair

C.Hinted handoff

D.Speculative retry

Explanation: With hinted handoff, the coordinator stores a hint for a write destined for an unavailable replica. When that replica comes back online within the hint window, the coordinator replays the hint so the replica catches up, helping maintain eventual consistency.

7On the Cassandra write path, where is data first recorded to guarantee durability before it is acknowledged?

A.Directly into an SSTable on disk

B.Into the commit log and the memtable

C.Into a secondary index file

D.Into the row cache only

Explanation: A write is appended sequentially to the commit log (for durability) and simultaneously applied to an in-memory memtable. Once both occur on enough replicas to satisfy the consistency level, the write is acknowledged. Memtables are later flushed to immutable SSTables.

8Which statement about SSTables in Cassandra is correct?

A.SSTables are immutable once written and merged later by compaction

B.SSTables are mutable and updated in place when a row changes

C.SSTables store only the commit log header

D.SSTables hold data only in memory until the node restarts

Explanation: SSTables (Sorted String Tables) are immutable on-disk files produced when a memtable is flushed. Because they are never modified in place, updates and deletes create new entries (or tombstones), and compaction later merges multiple SSTables to reconcile data and reclaim space.

9During a read, which structure helps Cassandra quickly skip SSTables that cannot contain the requested partition key?

A.Bloom filter

B.Commit log

C.Materialized view

D.Hint file

Explanation: Each SSTable has an associated Bloom filter, a probabilistic structure that tells Cassandra whether a partition key is definitely not present. This lets the read path avoid scanning SSTables that cannot contain the key, reducing disk I/O on reads.

10What role does the coordinator node play in a Cassandra read or write request?

A.It is always the node that physically owns every replica of the data

B.It is a dedicated master node elected for the whole cluster

C.It is the node the client connects to, which routes the request to the correct replicas

D.It only handles schema changes, never data operations

Explanation: Any node can act as the coordinator for a request. The client connects to one node, and that node forwards the operation to the replicas that own the partition, gathers the responses needed to satisfy the consistency level, and returns the result to the client.

About the Apache Cassandra Developer Associate Exam

The Apache Cassandra Developer Associate certification from DataStax validates the ability to model data and build applications on Apache Cassandra using CQL. It maps to the DataStax Academy developer learning path of DS201 (Foundations of Apache Cassandra) and DS220 (Data Modeling). The exam emphasizes the developer role, query-first data modeling, partition and clustering key design, denormalization, and CQL features such as collections, user-defined types, materialized views, and batches, rather than cluster operations. Candidates must also understand Cassandra's distributed architecture, tunable consistency levels, lightweight transactions, and TTL well enough to design correct, performant schemas.

Questions

60 scored questions

Time Limit

90 minutes

Passing Score

70% (42 of 60)

Exam Fee

$145 (DataStax)

Apache Cassandra Developer Associate Exam Content Outline

20-25%

Cassandra architecture and distributed-systems fundamentals

Understand ring topology and the Murmur3 partitioner, replication strategies (SimpleStrategy vs NetworkTopologyStrategy), gossip, snitches, hinted handoff, read repair, compaction, tombstones, and the commit-log, memtable, and SSTable read and write paths.

30-35%

Data modeling

Apply query-first design: pick partition keys for even distribution, use clustering columns for ordering and range queries, denormalize into table-per-query designs, use Chebotko diagrams, bound partition growth with time bucketing, and avoid anti-patterns like unbounded partitions and ALLOW FILTERING.

25-30%

CQL and storing/retrieving data

Write CQL to create keyspaces and tables, perform INSERT/UPDATE/DELETE/SELECT upserts, manage collections (set, list, map) and user-defined types, use frozen types, secondary indexes, materialized views, and batches, and apply LIMIT, ORDER BY, and TOKEN().

15-20%

Tunable consistency, transactions, and TTL

Choose consistency levels (ONE, QUORUM, LOCAL_QUORUM, ANY), apply the R + W > RF strong-consistency rule, use lightweight transactions (Paxos) and counters appropriately, set USING TTL and USING TIMESTAMP, and reason about last-write-wins conflict resolution.

How to Pass the Apache Cassandra Developer Associate Exam

What You Need to Know

Passing score: 70% (42 of 60)
Exam length: 60 questions
Time limit: 90 minutes
Exam fee: $145

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

Apache Cassandra Developer Associate Study Tips from Top Performers

1Master query-first modeling: list the application's read queries first, then design one denormalized table per query with a partition key that distributes load evenly.

2Drill the partition key versus clustering column distinction, including composite partition keys with double parentheses and the rule that the full partition key must be supplied in the WHERE clause.

3Memorize the consistency levels and the R + W > RF rule; for RF=3 know that QUORUM equals 2 replicas and that QUORUM read plus QUORUM write gives strong consistency.

4Know why ALLOW FILTERING, unbounded partitions, large multi-partition batches, and high-cardinality secondary indexes are anti-patterns, and what to do instead (bucketing, table-per-query, denormalization).

5Practice CQL features hands-on in cqlsh or Astra DB: collections (set, list, map), frozen UDTs, materialized views, counters, USING TTL, and LWTs with IF NOT EXISTS.

6Understand the write and read paths (commit log, memtable, SSTable, Bloom filter) and how tombstones, gc_grace_seconds, and repair interact to avoid zombie data.

Frequently Asked Questions

What are the exam facts for the Cassandra Developer Associate certification?

The DataStax Apache Cassandra Developer Associate exam has 60 questions, runs 90 minutes, and requires 70% (42 of 60) to pass. The fee is $145 USD, though a free voucher is commonly offered after completing the DataStax Academy developer learning path. It is delivered online with remote proctoring.

How is the developer exam different from the Cassandra administrator exam?

The developer path (DS201 plus DS220) focuses on CQL and data modeling: partition and clustering key design, denormalization, collections, UDTs, and consistency for application development. The administrator path (DS201 plus DS210) instead emphasizes cluster operations such as deployment, configuration, repair, and tuning.

Which courses prepare me for the Cassandra Developer exam?

DataStax recommends DS201 (Foundations of Apache Cassandra) for architecture and CQL basics, and DS220 (Data Modeling) for query-first design, partition keys, clustering columns, denormalization, and Chebotko notation. They are recommended but not strictly required.

What is the most important data-modeling principle tested?

Query-first design: identify the application's read queries first, then build one denormalized table per query. The partition key should distribute data evenly, clustering columns should order rows for the query, and partitions should stay bounded to avoid hot or oversized partitions.

Do I need to know consistency levels for the developer exam?

Yes. You should know ONE, QUORUM, LOCAL_QUORUM, and ANY, the strong-consistency rule R + W > RF (for RF=3, QUORUM reads and writes give 2 + 2 > 3), lightweight transactions via Paxos, and last-write-wins conflict resolution.

Is the Cassandra Developer certification relevant to DataStax Astra DB?

Yes. Astra DB is a serverless Cassandra-as-a-service built on Apache Cassandra, so the same CQL and data-modeling principles apply. Astra DB adds REST, GraphQL, and Document APIs and uses a secure connect bundle with an application token for connections.